Science Mapping the Academic Knowledge on Business Improvement Districts

Abstract

Business Improvement Districts (BIDs) are a contemporary urban revitalization policy that has been set in motion through international policymaking circuits. They have been presented as a panacea to the economic and social challenges facing many cities and traditional shopping districts. However, a comprehensive overview of the academic literature on this form of local governance remains to be conducted. Drawing on bibliometric methods and bibliometrix R-tool, this paper maps and examines the state-of-the-art of academic knowledge on BIDs published between 1979 and 2021. Findings suggest that (i) scientific production has increased since the early 2000s, has crossed US borders but remains highly Anglo-Saxon-centered; (ii) academic knowledge on BIDs is multidisciplinary and has been published in high-impact journals; (iii) influential documents on BIDs have centered on three issues: urban governance/politics, policy mobilities–mutation and impacts assessment and criticisms; (iv) while author collaboration networks exist, the interaction between them is limited; (v) the conceptualization of BIDs has changed over time, both in thematic and geographical focus. These results constitute the first science mapping on the academic literature on BIDs, and we argue they should inform future scientific debates about the studying of this form of local governance.

1. Introduction

Each year, the eyes of millions of revelers from all over the world are focused on the Times Square New Year’s Eve Ball. As the countdown progresses and the Ball begins its descent, the New York City borough of Manhattan is gripped by a large-scale hysteria as throngs of revelers celebrate the beginning of a new year. However, in the 1970s and 1980s, Times Square’s reputation was a far cry from the experience economy that is now part of its identity. World premieres of peep shows in local theaters and the spread of broken bottles, lost syringes and triple X adults shops in the neighborhood enlighten why Times Square was described as a ‘red-light district’ [1,2,3]. In the late 1980s, though, a group of property owners, together with the New York City government, decided to design a local revitalization plan focused on standard-bearer initiatives, including the Times Square New Year’s Eve. These initiatives were funded through property assessments and were implemented after the creation of the then Times Square Business Improvement District (BID) in 1992 [4].

New York City’s BIDs—a geographically bounded area in which property owners and/or business occupiers democratically vote to pay an assessment or levy that is ring-fenced for financing supplementary placemaking services, such as cleaning, security and branding—and their success revitalization stories have spread across international circuits of policymaking [5,6]. BIDs have been politically and socially constructed as a magic bullet to solve the problems of the vitality of traditional shopping districts in terms of security, safety and informal street vending [7], real estate appraisal [8], retail performance [9] and pedestrian experience [10]. Thus, New York City’s BIDs and their evidence-based triumphs acted as ‘inspiring prototypes’ in a wide range of global circuits of knowledge to induce international policy learning and exchange [5,6,11]. Predictably, over the past three decades, BIDs have crossed the US borders and spread to Australia, New Zealand and South Africa in the 1990s and England, Wales, Scotland and Germany in the early 2000s [5,12,13]. BIDs have also been territorialized in Northern Ireland, the Netherlands and Japan, while other countries have recently set up pilot initiatives and discussed the politics of their formation [14,15].

While BIDs have been set in motion from specific ‘sites of invention’ to different ‘sites of emulation’ over the last few decades, a comprehensive and systematic overview of the academic research on BIDs remains to be conducted. In mapping academic literature on BIDs over time, the aim of this paper is fourfold. Firstly, we want to trace the rhythms of scientific production on BIDs by analyzing how academic knowledge on this new scheme of local governance has evolved in temporal and spatial terms. Secondly, we want to characterize and document the global influence of academic knowledge on BIDs by mobilizing three units of analysis: authors, to identify who are the most influential scholars, when their scientific contribution appeared and how it has evolved; sources, to find out where scientific knowledge on BIDs is published and, thus, epistemically circulated; and documents, to discuss what has structured the thematic scope of the academic literature on BIDs. Thirdly, drawing on epistemic networks analysis, we focus on institutional and authorship networks formed in the study of BIDs to describe and discuss the making of collaboration communities. Fourthly, we aim to briefly dialogue with the main research fronts that have emerged and been increasingly discussed in the academic knowledge on BIDs.

To address these points, this paper draws on bibliometric techniques as tools that assemble bibliographic data from scientific databases to quantitatively measure and monitor a small but growing scientific field in order to longitudinally determine its evolution, intellectual structure and performance [16,17]. Based on these techniques, conducted in the bibliometrix R-tool and complemented by a qualitative literature review [18], this paper aims to shorten the gap in academic knowledge about a much-heralded contemporary urban and economic revitalization policy and advance and inform recent debates on the BID literature by analyzing the most prominent scientific knowledge, epistemic communities and longitudinal thematic shifts.

This article is structured as follows. Section 2 conceptually introduces BIDs as a new form of local governance in motion aimed at revitalizing traditional shopping districts. The paper moves on to outline its methodological framework. Section 4 provides a comprehensive science mapping on the academic literature on BIDs by analyzing its rhythms of scientific production, relevant authors, sources and documents and influential epistemic communities and networks formed throughout the last decades. Section 4 ends with a longitudinal examination of the intellectual and thematic trends on BIDs. The paper closes with a discussion of the main findings and their contributions to present and future academic debates on BIDs.

2. Business Improvement Districts (BIDs): Policy Origins and Characteristics

BIDs emerged in North America as an entrepreneurial and business-led response to the destructive effects that residential and retail suburbanization, industrial decline and restructuring and shrinking tax bases had inflicted on traditional shopping districts over the decades [5,12,19]. The formation of the first BID dates back to 1970 in Runnymede-Bloor West Village (Toronto) when some members of the local businesspeople association realized that their businesses were struggling due to the out-of-town retail development and metro line expansion in the 1950s and 1960s [20]. Simultaneously, the voluntary-based funding mechanisms and, thus, the prevalence of numerous free-riders (i.e., local members who do not contribute to the revitalization initiatives while benefitting from them) led to the failure of several promotional activities arranged by the local businesspeople association [20,21]. Therefore, in the late 1960s, local businesses and authorities jointly encouraged the creation of a business district where any revitalization initiative would be financed by a compulsory levy imposed on all local businesses [5,12].

BIDs were subsequently territorialized in the US when Downtown Development District in New Orleans became the first US BID in 1974. Since then, BIDs have become prominent actors in urban governance in US downtowns over the past three decades, thriving from 400 BIDs in 1999 to over 2000 in 2010 [22,23]. As in Canada, in addition to the out-of-town retail expansion, US BIDs have also flourished as an entrepreneurial form of governance in response to the fiscal shrinkages and their ‘suburban flight’ that undermined the effectiveness and efficiency of the management of traditional urban spaces [24,25].

Claimed to have changed “the way America governs its shopping districts, commercial areas and downtowns” [26] (p. 374), the US BIDs success stories—largely located in New York, Philadelphia and Washington—were taken from their ‘sites of operation’ and circulated through international policymaking infrastructures as best practices in revitalizing downtown’s business climate. For instance, Daniel Biederman—co-founder of Bryant Park Foundation, 34th Street Partnership and Grand Central Partnership in Manhattan—traveled the world stating that “getting political leaders to sign off on the BID was rocket science because no one wanted to privatize a park. But look at the result today: Bryant Park is a gem” [27]. Inspired by such success narratives, BIDs were set in motion and eventually reached Australia, New Zealand and South Africa in the late 1990s [5,12] and England, Wales, Scotland and Germany in the early 2000s [28,29,30]. In the 2010s, BIDs have also been contextualized in Northern Ireland [30], the Netherlands [31], Japan [32], Serbia [33], Albania and Spain [34]. While some have argued that BIDs also exist in Denmark and Sweden [14,35], their legal institutionalization is yet to happen because these structures do not own legal ability to impose a mandatory levy on local stakeholders.

While on the move, BIDs have been heralded as “a more focused and flexible form of governance” [26] (p. 129). Their plasticity and resilience to adjust to different territorial contexts significantly contributed to the internationalization of this urban policy under different expressions. While BIDs are known as Business Improvement Areas/Zones in Canada, City Improvement Districts in South Africa and Urban Improvement Districts in Germany and the Netherlands, in the US their epithet is state-dependent (e.g., Special Improvement Districts in New Jersey and Ohio; Community Improvement Districts in Georgia and Public Improvement Districts in Texas). In the UK, they are largely known as BIDs, except in Scotland, where they are easily known as Improvement Districts [36,37]. Independently of where they operate, BIDs share some general features [25,36,37,38]. First, they are geographically delimited areas managed through a strategic partnership between private and public sectors for a limited period. Second, although BIDs are only set up based on existing public-enacted regulations, their creation and management are dependent on private-sector agency (property owners and/or business occupiers). Third, BIDs are self-rating areas where all private stakeholders democratically decide to pay a mandatory assessment or levy. Fourth, the resulting proceeds are locally ring-fenced to provide additional public services focused on the political economy of the place and ensure that BID members’ concerns are addressed in urban politics [22,39,40]. A BID can, thus, be defined as a geographical area, empowered by local authorities, in which local private stakeholders mutually agree to pay an assessment or levy that is ring-fenced for funding supplementary placemaking programs aimed at enhancing the experience economy and urban livability of the area.

3. Materials and Methods

This paper aims to examine academic literature on BIDs by analyzing its temporal and spatial rhythms, influential authors, sources and documents and mapping author collaboration networks and recent thematic trends. Thus, this study draws on bibliometric methods to conduct a systematic and objective literature review. Bibliometric analyses—a quantitative approach that mobilizes bibliographical data to describe and examine academic literature—have become reliable approaches to inform subsequent stages of literature review without the subjective bias in which traditional narrative reviews are often embedded [16,17,41]. In this paper, bibliometric methods were employed with two main aims. First, as measures of influence to evaluate the performance of scholars, sources and documents on BIDs. Second, to visualize structural and intellectual networks in a specific research field through science mapping techniques, which facilitate the description, interpretation and visualization of the state-of-the-art of academic knowledge and its production and intellectual dynamics over time [17,42,43].

3.1. Data Collection

Bibliographical data used in this paper were retrieved from one of the largest abstract and citation databases of peer-reviewed literature: Scopus. While other scientific databases, such as Thomson Reuters’ Web of Science (WoS), constitute additional sources of bibliographical data, Elsevier’s Scopus database has been described as more comprehensive to assess research impact in social sciences [44,45,46]. Furthermore, there is an increasing overlap of journal titles between WoS and Scopus databases [46].

Our review protocol comprised four phases. Firstly, the scope of the study was limited to BID-related terms to include accurate publications. As discussed earlier, BIDs have different nomenclatures depending on the socio–spatial and political–institutional settings where they are placed. Thus, a wide variety of BID designations, combined with Boolean operators, were included in the search protocol (

Table 1. Search terms included in the review protocol ¹.

1. Business Improvement District	12. Local Improvement District
2. City Improvement District	13. Municipal Improvement District
3. Community Benefit District	14. Municipal Service District
4. Community Development District	15. Neighborhood Improvement District
5. Community Improvement District	16. Principal Shopping District
6. Downtown Development District	17. Public Improvement District
7. Downtown Improvement District	18. Special Assessment District
8. Downtown Management District	19. Special Benefit District
9. Economic Development District	20. Principal Shopping District
10. Improvement District	21. Special Service District
11. Local Improvement District	22. Urban Improvement District

¹ The variants “Area” and “Zone” were also considered, including in their plural forms.

). This protocol was performed on the 19th of November 2021 and a total of 1242 documents were retrieved (Figure 1).

In the second phase, retrieved records were restricted to journal articles, conference papers, literature reviews, book chapters and books [45]. Other document types, such as letters, short surveys, editorials and notes, were excluded from the analysis as they were not considered to have undergone a rigorous peer-review process [47]. Furthermore, no exclusion criteria were defined based on publication date, scientific area and language in which records were produced. These inclusion and exclusion criteria provide methodological flexibility to retrieve a broader number of publications on BIDs without considering when, where and in what language they were produced. According to these criteria, 20 documents were excluded.

Thirdly, evidence suggests that, although search terms are carefully chosen, retrieved documents are not always within the scope of the review, which may undermine the reliability of the analysis [17,18]. Therefore, the qualitative screening of titles and abstracts is a recommended method to improve the accuracy of the results. While this approach may introduce subjective bias into the analysis, one of the authors of this paper performed the screening and, in case of skepticism about the eligibility of any document, peer debrief meetings were conducted [48]. Each document was, thus, coded considering its thematic scope, resulting in the exclusion of 982 records (79.1%). Data organization and codification were conducted using MaxQDA2020 software.

Finally, after removing duplicates (1), 239 documents were included in the review: 199 journal articles (83.2%), 15 book chapters (6.3%), 14 reviews (5.9%), 7 conference papers (2.9%) and 4 books (1.7%). These core documents were then compiled in a single database extracted from Scopus (BibTeX) with the following bibliographical data: document title, document type and language, authors and their institutional affiliations, keywords, abstract, number of citations, journal name, publication date, volume, issue number and a list of cited references. Subsequently, we proceeded to conduct data cleaning using Texmaker software to detect misspelled elements and ensure database consistency as, for example, some authors’ names were wrongly abbreviated (e.g., Lorlene Hoyt appeared as “Hoyt, L.” and “Hoyt, L.M.”). These procedures are critical when authors and journals constitute the units of analysis [17,18].

3.2. Data Analysis

In this paper, bibliometric review involves both descriptive and hermeneutic analysis considering four different units of analysis. While several bibliometric and science mapping software tools exist and have been compared elsewhere [17,18], this study draws on the recent R-package tool—bibliometrix. Bibliometrix is a recent package for the R statistical programming language that employs specific tools for quantitative research in bibliometrics and scientometrics [18,49]. After database cleaning (see Section 3.1), bibliographical data from eligible core documents were imported to the R data frame for subsequent analysis.

Firstly, a descriptive analysis of three bibliometric units of analysis—authors, sources and documents—was conducted. We started by outlining the academic knowledge pro-duction rhythms on BIDs to trace its temporalities and spatialities over the last decades. Subsequently, drawing on two bibliometric methods—citation and co-citation analysis—we measured the influence of the most relevant academics working on BIDs, uncovered the sources where academic knowledge on BIDs is published, listed the documents that have influenced scientific knowledge on BIDs and discussed their thematic scope.

Citation methods are commonly used as measures of influence [50]. This argument rests on the principle that heavily cited authors, sources and documents are relevant to assess the productivity, efficiency and impact of a specific research field [17,50,51,52]. These metrics are often supplemented by other citation impact indicators, such as citations per document, H-index or journal’s impact factors [50,51,52,53]. In addition to these, co-citation analysis also provides insights into the influence and similarity between authors (author co-citation analysis) and documents (document co-citation analysis) as it determines which and how often references included in core documents have been cited [54,55]. In this paper, both citation and co-citation methods were used to provide an intellectual performance assessment of the most relevant authors, sources and documents on BIDs.

Secondly, epistemic network analysis (or co-authorship analysis) is a well-documented technique used in bibliometric studies that rests on the assumption that co-authoring publications are a reliable measure of scientific collaboration between authors and their institutions [17,56,57]. Thus, co-authorship analysis connects authors that worked together in a specific research field. Drawing on this bibliometric technique, we detected both international and intra-national collaboration networks and briefly characterized the intellectual clusters and social structures of academic knowledge on BIDs.

Finally, co-word analysis—in which words are the unit of analysis—is a content analysis method that aims to structure a conceptual framework of a field by examining the most frequent words included in the documents, particularly in their titles, abstracts and keywords [17,18,58]. The conceptual representation of word co-occurrence analysis is a network of themes through which the cognitive structure of a scientific field is unveiled [57]. Through this visual tool, one can trace the longitudinal changes in the conceptual framework of a scientific area.

4. Results

4.1. Rhythms of Scientific Production on BIDs: Temporalities and Spatialities

BIDs emerged as a much-heralded inner-city shopping districts revitalization policy in the early 1970s and were set in motion through contemporary policymaking circuits in the following decades. Almost simultaneously with their creation in 1970 in Canada, BIDs flourished as a theme in academic literature; however, the temporal rhythms of scientific production on BIDs over the last decades do not describe a straight growth trajectory (Figure 2). Furthermore, these longitudinal patterns are closely related to the temporalities of the ‘transfer’ of this policy to different socio–spatial and political–institutional contexts.

Firstly, the volume of scientific production on BIDs was not significant until the mid-1990s. The only two publications produced in the 1970s and 1980s had as case studies BIDs in the Province of Ontario (Canada), which was the first to pass BID enabling legislation in 1970. Thus, the first paper was published in 1979 and examined Ontario’s BID program [59]. Similarly, in the 1980s, only one document on BIDs was found, and Ontario was also the province under study [60].

Secondly, findings showed a moderate increase in scientific production on BIDs in the 1990s (9 documents). While Canada retained its pace of scientific production in the 1990s [61], the national distribution of published documents expanded to the US. This spatial trend is related to the rapid introduction of BID enabling legislation in several US states during the 1990s, which subsequently led to an increase in the scientific literature on the revitalization opportunities that BIDs could bring to the management of US downtowns and town centers [24,62,63,64]. It should be emphasized that R. Briffault [25] provided one of the most prominent and comprehensive documents on BIDs in the late 1990s. This paper examined in-depth the US BIDs’ institutional roots, their formation politics, as well as financial, operational and governance mechanisms and some of their main legal issues.

Thirdly, scientific production on BIDs increased considerably in the 2000s as 74 documents were published during this decade (54 of them after 2004). Such quantitative growth can be explained by a double process. On the one hand, it resulted from the extensive development of BIDs in the US during the 1990s. On the other hand, it derived from the international circulation of US BIDs’ successful revitalization narratives through policymaking circuits. Therefore, in the early 2000s, the first UK studies on BIDs, while conceptualizing them as an innovative and effective revitalization policy compared to the existing Town Center Management schemes, also made policy recommendations for the territorialization of BIDs in the UK [65,66,67]. Since then, discussion on BIDs’ trans-local expansion has increased, not only in the UK [12,28,36,68,69,70] but also in South Africa [71,72]. However, in the 2000s, scientific literature on BIDs remained highly US-centric and focused on examining BIDs’ performance [73,74,75,76,77] and their role in local and metropolitan governance [78,79,80,81,82].

Fourth, the number of publications on BIDs has more than doubled in the last decade, rising from 74 in the 2000s to 126 in the 2010s. Similarly, documents on BIDs published in the current decade are already 28, which suggests a growing trend in the academic literature. Over these two decades, academic knowledge has focused on the international circulation of BIDs in contexts other than the UK. The spreading of BIDs to South Africa [83,84,85,86] and Germany [29,87,88] emerged notably in the literature after 2012. Almost concurrently, the first documents referring to BID formation in Japan [32], Spain [89] and Nordic countries, such as Denmark [14] and Sweden [15,90], flourished during this fourth phase.

Unsurprisingly, national scientific production reflects the uneven geographies where BIDs have developed (Figure 3). US, UK and Canada are among the countries that have published more literature about BIDs, followed by Germany, South Africa and France.

4.2. Influential Authors, Sources and Documents on BIDs

When analyzing scientific production based on authorship criteria, findings demonstrate that the academics who have published more documents on BIDs are, of course, found in the US, UK, Canada and South Africa, where these forms of governance have longer institutional roots. The most scientifically active authors were G. Morçöl (9 documents), K. Ward (8 documents), G. Lloyd (6 documents), E. Peyroux (6 documents) and I. Cook, R. Lippert, B. Michel and D. Peel (5 documents each).

However, citation analysis provides a different mapping as some of the authors who have published more documents on BIDs are not the most influential (

Table 2. Most prominent academics publishing on BIDs, 1979–2021.

Rank	Author	Country	Total Documents	Scopus Cites	Cites Per Document	Scopus H-Index 1
1	K. Ward	UK	8	914	114.3	44
2	E. McCann	Canada	3	449	149.7	28
3	I. Cook	UK	4	309	62.0	12
4	G. MacLeod	UK	1	224	224.0	31
5	R. Briffault	USA	1	186	186.0	12
6	L. Hoyt	USA	4	183	45.8	5
7	E. Peyroux	France	6	154	25.7	7
8	J. MacDonald	USA	3	134	44.7	37
9	J. Mitchell	USA	2	131	65.5	5
10	S. Didier	South Afr	3	124	41.3	7
11	G. Lloyd	UK	6	118	19.7	19
12	J. Hackworth	Canada	1	109	109.0	17
13	J. Rekers	Canada	1	109	109.0	8
14	M. Morange	France	2	105	52.5	7
15	F. Miraftab	USA	2	104	52.0	19

¹ H-Index is a scientific performance indicator that quantifies the number of papers that have been cited, at least, H times [51,53].

). While G. Morçöl, R. Lippert, B. Michel and D. Peel are among the most active scholars writing on BIDs, their studies are not heavily cited and, thus, are not yet considered to be important in this field. According to the citation analysis, K. Ward is the most influential scholar on BIDs (914 citations), followed by E. McCann (449 citations) and I. Cook (309 citations). However, G. MacLeod and R. Briffault, who published a single document, are among the most cited scholars, thus suggesting that their publications are seminal in the scientific knowledge on BIDs (224 and 186 citations, respectively).

As discussed earlier, the longitudinal analysis of scientific production on BIDs dis-closed a significant increase in the published documents since the early 2000s, particularly after BID institutionalization in Great Britain. Accordingly, the number of authors writing on BIDs has also increased, thus suggesting a growing interest among different academics in this form of local governance. For instance, while in 2003 only two of the 15 most productive authors were actually publishing on BIDs (G. Lloyd and G. Warnaby), this figure increased to about ten authors working on BIDs annually in the late 2000s and early 2010s. Nonetheless, different longitudinal profiles of scientific production and academic influence can be traced (Figure 4).

Firstly, some of the publications on BIDs emerged out of research projects, some of which were funded, some of which were not. K. Ward’s earliest publications [5,19,36,91], for example, were produced out of an unfunded program of research centered on exploring how BIDs came to be introduced into England in the early 2000s. L. Hoyt analyzed BIDs organizations worldwide in 2001–2002, which resulted in a set of publications [73,74,92]. E. Peyroux coordinated the research project “Privatization of Security in Sub-Saharan African Cities”, which discussed the role of new forms of governance, including BIDs, in public space securitization in South African cities [83,84,85,86]. J. Berg also collaborated in a policing project at the University of Cape Town, which resulted in her Ph.D. in 2015 [71,93]. Similarly, some scholars in Germany, headed by B. Michel and C. Stein, conducted a “comparative research project on trajectories of local implementations of BIDs in several different national and regional contexts” [13] (p. 76). This project resulted in some publications between 2013 and 2017 [29,87,88].

Secondly, some publications emerged out of doctoral studies. L. Brooks completed her Ph.D. in Economics in 2005 and published three articles between 2006 and 2008 [77,94,95]. Similarly, I. Cook, supervised by K. Ward, conducted his Ph.D. thesis on the ‘transfer’ of the US BIDs to England and their re-embedding in three urban areas between 2004 and 2008, which encouraged the publication of three articles between 2008 and 2010 [28,70,96]. Finally, W. Lee completed her Ph.D. in 2014 on the creation of BIDs in low-income neighborhoods in Los Angeles. She then published two papers in 2016 [97,98] and moved further into the BID field by integrating her expertise in social work with the homeless in BID areas [99,100].

Author co-citation analysis is an additional bibliometric method used to map the intellectual structure of a scientific field since it identifies the most influential scholars through quantifying the most cited authors according to the references list of each of the core documents [54,55]. In the case of BIDs, 7 of the 15 most cited authors were also among the 15 most co-cited authors (

Table 3. Most co-cited authors publishing on BIDs, 1979–2021.

Rank	Author	Country	Affiliation 1	Local Cites	Scopus H-Index
1	J. MacDonald	USA	Univ. of Pennsylvania	100	37
2	E. Peyroux	France	U. of Toulouse II	76	7
3	P.J. Cook	USA	Duke University	75	33
4	L. Hoyt	USA	MIT	71	5
5	R. Lippert	Canada	Univ. of Windsor	64	17
6	G. Morçöl	USA	Penn State Harrisburg	42	9
7	I. Cook	UK	Univ. of Northumbria	40	12
8	G. Lloyd	UK	Univ. of Dundee	38	19
9	S.E. Baer	USA	San Diego State Univ.	34	2
10	S. Didier	South Africa	French Inst. South Africa	33	7
11	M. Morange	France	Univ. of Paris Diderot	33	7
12	V.L. Marando	USA	Univ. of Maryland	31	8
13	J.S. Gross	USA	Hunter College	30	8
14	C. Stein	Germany	Goethe-Univ. Frankfurt	30	4
15	B. Michel	Germany	Martin-Univ. Halle-Wittenberg	29	8

¹ Institutional affiliation refers to the period of scientific production on BIDs.

). For example, J. MacDonald was the most highly cited local author as 100 of the retrieved documents cited, at least, one of his studies. In addition, E. Peyroux (76 local cites), P.J. Cook (75 local cites)—who benefited from academic collaboration with MacDonald–, L. Hoyt (71 local cites) and R. Lippert (64 local cites) were also the most-cited authors in the references found in retrieved documents.

Interestingly, some of the most influential authors in terms of total citations, such as K. Ward and E. McCann, were not among the most co-cited scholars. While these authors have built on a relatively small but growing thematic scope—policy mobilities—in their documents BIDs have only been examined as an example of a policy in motion. Contrariwise, although G. Morçöl was not one of the most heavily cited scholars, he is among the most co-cited authors due to his work relating BIDs to governance issues. Another conclusion that can be drawn from the co-citation analysis is that the most co-cited authors, in addition to the US, UK, France, Canada and South Africa, also include more recent academics based in Germany.

While some academics argue that what rather than where you publish is what matters, this assertion seems to be built on speculation as academia has been making intensive use of an ‘audit culture’ [51,52]. Journal-level indicators have become valuable metrics to assess a journal’s relative performance and influence. Eventually, the authors’ scientific performance is also calculated through these metrics. As noted earlier, scientific production on BIDs is mostly comprised of articles published in scientific journals (83.2%). Moreover, findings show that academic knowledge on BIDs is disseminated in journals with a heterogeneous thematic scope (

Table 4. Most prominent sources publishing on BIDs, 1979–2021.

Rank	Source	Country	Total Documents	Scopus Cites	CiteScore (2017–2020) 2	Scopus Quartile 2020
1	Urban Stud 1	UK	7	430	6.64	Q1
2	Geoforum 1	UK	4	369	5.53	Q1
3	Int J Urban Reg Res 1	UK	4	361	6.08	Q1
4	Eur Urban Reg Stud 1	UK	8	237	6.47	Q1
5	Int. J. Public Adm. 1	USA	11	225	2.43	Q2
6	Econ. Dev. Q. 1	USA	4	190	2.45	Q1
7	Columbia Law Rev	USA	1	186	2.44	Q1
8	Urban Aff Rev 1	USA	8	170	3.35	Q1
9	Antipode	UK	3	151	5.89	Q1
10	Policy Stud.	UK	1	150	2.86	Q1
11	Int Plan Stud.	UK	3	123	2.43	Q2
12	J Plan Educ Res	USA	3	113	5.63	Q1
13	Urban Geogr 1	UK	6	100	5.38	Q1
14	Environ. Plan A 1	UK	5	88	5.56	Q1
15	Econ. J.	USA	1	80	5.86	Q1

¹ Journals with the highest number of published documents on BIDs (Bradford’s Law). In addition to those displayed, J. Urban Regen. Renew. (9 papers), Local Econ. (5 papers) and Urban Res Pract (5 papers) are also considered core sources. ² CiteScore measures the performance and influence of scientific journals. It is a ratio between the number of citations and documents published in a scientific journal.

). While most of the journals are related to urban/regional, geography/planning and political science studies, debates on BIDs are also found in other scientific areas, such as economics, law and public administration.

Similar to the authors, findings suggest that journals publishing the largest number of documents on BIDs are not necessarily the most influential. While the International Journal of Public Administration (11 documents, 9 of which were published in a Special Issue in 2006), Journal of Urban Regeneration and Renewal (9 documents, all of them published since 2013), European Urban and Regional Studies (8 documents, 5 of which published in a Special Issue in 2012), Urban Affairs Review (8 documents), Urban Studies (7 documents) and Urban Geography (6 documents) were the core source journals with the greatest scientific production on BIDs, some of them were not the most heavily cited. First, Urban Studies, Geoforum and International Journal of Urban and Regional Research were the most cited journals. Second, although some core sources such as the Journal of Urban Regeneration and Renewal, Local Economy and Urban Research and Practice have produced a wide number of documents on BIDs, these were not considered to be influential as their total number of citations is low (18, 26 and 22 citations, respectively). Third, we found two journals—Columbia Law Review (186 citations) and Policy Studies (150 citations)—that, while having published a single document on BIDs, were among the most cited, thus suggesting that these publications have become seminal works.

Finally, scientific production on BIDs is found in journals with a high impact factor. Findings show that 13 of the 15 most cited journals publishing on BIDs are indexed as Q1 in the Scopus database and the remainders are ranked as Q2. This suggests that most heavily cited documents are found in journals of higher quality and scientific impact.

We now turn our attention to documents as a bibliometric unit of analysis to uncover the conceptual framework of a given research field. Document citations and the studies cited in these documents are two techniques that measure publications’ scientific relevance and quality [45,50]. In the literature on BIDs, about half of the 15 most cited studies included in this review were issued in the last decade and in high-impact journals (Table 5).

The most cited document on BIDs, authored by E. McCann and K. Ward, examined how urban policies—illustrated by the ‘transfer’ of BIDs from the US to England—were mutually constituted in relation with other places and how they were territorialized in different contexts [101]. This paper is a remarkable example of the emergence of a thematic line on BIDs—policy mobilities and mutation—that has gained relevance over the last decade [102], with 9 of the 15 most cited documents focusing on the mobility, mutation and ‘transfer’ of BIDs to different socio–spatial and institutional contexts. For example, Hoyt’s pioneering study explored how BIDs were transferred both intra- and inter-nationally [12]. More recently, Ward and Cook studied the ‘transfer’ of the BID ‘model’ from the US to the UK [28,36,38] and Sweden [103], while Miraftab [72] and Didier, Peyroux and Morange [84] focused on the circulation of BIDs to South Africa within an entrepreneurial governance framework.

The second body of literature is, thus, closely related to the relationship between BIDs and neoliberal state restructuring and their consequences for urban politics. While heavily cited studies on BIDs often discuss the rise of entrepreneurial governance to frame their international circulation, some of these studies focus entirely on this thematic line. For example, MacLeod [104], Miraftab [72] and Didier, Peyroux and Morange [84] discussed how BIDs in South Africa had become an urban revitalization policy that informs the shifts that urban management and governance have recently experienced. These works also emphasize how BIDs, as a neoliberal policy introduced in a post-apartheid context, continue to reproduce the long-lasting social and spatial inequalities in some contemporary cities. However, Briffault [25] and, to a lesser extent, Mitchell [22] provided the first comprehensive discussions on BIDs’ formation politics and their operational and financial mechanisms in the US.

Table 5. Most relevant documents published on BIDs, 1979–2021.

Rank	Authors	Year	Title	Scopus Cites	Main Thematic Scope 1
1	McCann & Ward	2010	Relationality/territoriality: Toward a conceptualization of cities in the world [101]	293	Pol. Mob. Mut.
2	Ward	2006	‘Policies in motion’, urban management and state restructuring: The trans-local expansion of Business Improvement Districts [36]	274	Pol. Mob. Mut.
3	MacLeod	2011	Urban politics reconsidered: Growth machine to post-democratic city? [104]	224	Urb Gov. Polit.
4	Briffault	1999	A government for our time? Business improvement districts and urban governance [25]	186	Urb Gov. Polit. Impact. Critic.
5	McCann & Ward	2013	A multi-disciplinary approach to policy transfer research: Geographies, assemblages, mobilities and mutations [102]	150	Pol. Mob. Mut.
6	I. Cook	2008	Mobilising urban policies: The policy transfer of US business improvement districts to England and Wales [28]	140	Pol. Mob. Mut.
7	Hackworth & Rekers	2005	Ethnic packaging and gentrification: The case of four neighborhoods in Toronto [105]	109	Impact. Critic.
8	Mitchell	2001	Business Improvement Districts and the “New” Revitalization of Downtown [22]	101	Urb Gov. Polit.
9	I. Cook & Ward	2012	Conferences, informational infrastructures and mobile policies: The process of getting Sweden ‘BID ready’ [103]	94	Pol. Mob. Mut.
10	Miraftab	2007	Governing post-apartheid spatiality: Implementing city improvement districts in Cape Town [72]	81	Pol. Mob. Mut. Urb Gov. Polit.
11	P. Cook & MacDonald	2011	Public Safety through Private Action: An Economic Assessment of BIDs [106]	80	Impact. Critic.
12	Hoyt	2006	Importing ideas: The transnational transfer of urban revitalization policy [12]	72	Pol. Mob. Mut.
13	Tait and Jensen	2007	Travelling ideas, power and place: The cases of urban villages and business improvement districts [107]	56	Pol. Mob. Mut.
14	Ward	2007	“Creating a personality for downtown”: Business improvement districts in Milwaukee [91]	55	Urb. Gov. Polit.
15	Didier, Peyroux & Morange	2012	The spreading of the CID Model in Johannesburg and Cape Town: Urban regeneration and the neoliberal agenda in South Africa [84]	55	Pol. Mob. Mut.

¹ Pol. Mob. Mut—Policy Mobilities and Mutation; Urb. Gov. Polit.—Urban Governance and Politics; Impact. Critic.—Impacts and Criticisms.

Table 5. Most relevant documents published on BIDs, 1979–2021.

Rank	Authors	Year	Title	Scopus Cites	Main Thematic Scope 1
1	McCann & Ward	2010	Relationality/territoriality: Toward a conceptualization of cities in the world [101]	293	Pol. Mob. Mut.
2	Ward	2006	‘Policies in motion’, urban management and state restructuring: The trans-local expansion of Business Improvement Districts [36]	274	Pol. Mob. Mut.
3	MacLeod	2011	Urban politics reconsidered: Growth machine to post-democratic city? [104]	224	Urb Gov. Polit.
4	Briffault	1999	A government for our time? Business improvement districts and urban governance [25]	186	Urb Gov. Polit. Impact. Critic.
5	McCann & Ward	2013	A multi-disciplinary approach to policy transfer research: Geographies, assemblages, mobilities and mutations [102]	150	Pol. Mob. Mut.
6	I. Cook	2008	Mobilising urban policies: The policy transfer of US business improvement districts to England and Wales [28]	140	Pol. Mob. Mut.
7	Hackworth & Rekers	2005	Ethnic packaging and gentrification: The case of four neighborhoods in Toronto [105]	109	Impact. Critic.
8	Mitchell	2001	Business Improvement Districts and the “New” Revitalization of Downtown [22]	101	Urb Gov. Polit.
9	I. Cook & Ward	2012	Conferences, informational infrastructures and mobile policies: The process of getting Sweden ‘BID ready’ [103]	94	Pol. Mob. Mut.
10	Miraftab	2007	Governing post-apartheid spatiality: Implementing city improvement districts in Cape Town [72]	81	Pol. Mob. Mut. Urb Gov. Polit.
11	P. Cook & MacDonald	2011	Public Safety through Private Action: An Economic Assessment of BIDs [106]	80	Impact. Critic.
12	Hoyt	2006	Importing ideas: The transnational transfer of urban revitalization policy [12]	72	Pol. Mob. Mut.
13	Tait and Jensen	2007	Travelling ideas, power and place: The cases of urban villages and business improvement districts [107]	56	Pol. Mob. Mut.
14	Ward	2007	“Creating a personality for downtown”: Business improvement districts in Milwaukee [91]	55	Urb. Gov. Polit.
15	Didier, Peyroux & Morange	2012	The spreading of the CID Model in Johannesburg and Cape Town: Urban regeneration and the neoliberal agenda in South Africa [84]	55	Pol. Mob. Mut.

¹ Pol. Mob. Mut—Policy Mobilities and Mutation; Urb. Gov. Polit.—Urban Governance and Politics; Impact. Critic.—Impacts and Criticisms.

A third and last body of literature found in the most cited documents is connected to BIDs’ impacts assessment and criticisms. While this research line has gained traction in more recent years, two of the most cited articles have already discussed the consequences of adopting entrepreneurial schemes of urban governance in North America. Hackworth and Rekers [105] found that 4 BIDs in Ontario (Canada) served as market tools to promote residential and commercial gentrification in specific shopping districts, while Cook and MacDonald [106] concluded that in areas where BID-financed security services were in place, crime levels were lower when compared to non-BID areas.

Although the number of total citations is one of the most used bibliometric metrics to identify influential documents, this technique is embedded in some methodological glitches because it also considers citations that can go beyond other issues that of BIDs [45,50]. Thus, some studies argue that the most cited local documents (i.e., measures how many times a document in the retrieved collection has been cited by other documents in the same collection) are a more reliable metric to evaluate the most influential scientific publications. In the case of BIDs, findings showed significant differences between global (Table 5) and local cited publications (Table 6), indicating that some heavily cited documents have a stronger relationship with external issues than with BID-related ones.

Firstly, the 15 most local-cited documents have a higher mean year of publication (2003) when compared to the ones with more global citations (2008). In the references lists of the core documents included in this review, the most cited ones were Mallett [24], Briffault [25] and Mitchell [22,108]. These studies provided the first comprehensive overview of the foundational and basic principles of the BIDs. Unsurprisingly, studies on BIDs tend to draw on these seminal works to conceptually introduce this form of governance and its origins while discussing their main operational characteristics in terms of service delivery and regulatory activities. While Briffault’s conceptual study is the most cited paper among the core documents included in this review, Mitchell also conducted the first US BIDs national survey to understand how these organizations have delivered different placemaking activities.

Table 6. Most relevant local-cited documents published on BIDs, 1979–2021.

Rank	Authors	Year	Title	Total Cites	Main Thematic Scope 1
1	Briffault	1999	A government for our time? Business improvement districts and urban governance [25]	75	Urb. Gov. Polit. Impact. Critic.
2	Mitchell	2001	Business Improvement Districts and the “New” Revitalization of Downtown [22]	48	Urb. Gov. Polit.
3	Ward	2006	‘Policies in motion’, urban management and state restructuring: The trans-local expansion of BIDs [36]	40	Pol. Mob. Mut.
4	I. Cook	2008	Mobilising urban policies: The policy transfer of US business improvement districts to England and Wales [28]	31	Pol. Mob. Mut.
5	Hoyt	2006	Importing ideas: The transnational transfer of urban revitalization policy [12]	28	Pol. Mob. Mut.
6	Lloyd, McCarthy, McGreal and Berry	2003	Business Improvement Districts, Planning and Urban Regeneration [65]	23	Pol. Mob. Mut.
7	Morçöl and Zimmermann	2006	Metropolitan Governance and Business Improvement Districts [82]	22	Urb. Gov. Polit.
8	Mallett	1994	Managing the Post-Industrial City: Business Improvement Districts in the United States [24]	22	Urb. Gov. Polit.
9	Gross	2005	Business Improvement Districts in New York City’s Low-Income and High-Income Neighborhoods [109]	21	Urb. Gov. Polit.
10	Hoyt	2005	Do Business Improvement District organizations make a difference? Crime in and around commercial areas in Philadelphia [73]	20	Impact. Critic.
11	Mitchell	2001	Business Improvement Districts and the Management of Innovation [108]	19	Urb. Gov. Polit.
12	Hochleutner	2003	BIDs fare well the democratic accountability of business improvement districts [110]	19	Impact. Critic.
13	Brooks	2008	Volunteering to be taxed: Business improvement districts and the extra-governmental provision of public safety [77]	18	Impact. Critic.
14	Hoyt	2004	Collecting private funds for safer public spaces: An empirical examination of the Business Improvement District concept [74]	18	Impact. Critic.
15	Levy	2001	Paying for the Public Life [26]	17	Urb. Gov. Polit. Impact. Critic.

¹ Pol. Mob. Mut—Policy Mobilities and Mutation; Urb. Gov. Polit.—Urban Governance and Politics; Impact. Critic.—Impacts and Criticisms.

Table 6. Most relevant local-cited documents published on BIDs, 1979–2021.

Rank	Authors	Year	Title	Total Cites	Main Thematic Scope 1
1	Briffault	1999	A government for our time? Business improvement districts and urban governance [25]	75	Urb. Gov. Polit. Impact. Critic.
2	Mitchell	2001	Business Improvement Districts and the “New” Revitalization of Downtown [22]	48	Urb. Gov. Polit.
3	Ward	2006	‘Policies in motion’, urban management and state restructuring: The trans-local expansion of BIDs [36]	40	Pol. Mob. Mut.
4	I. Cook	2008	Mobilising urban policies: The policy transfer of US business improvement districts to England and Wales [28]	31	Pol. Mob. Mut.
5	Hoyt	2006	Importing ideas: The transnational transfer of urban revitalization policy [12]	28	Pol. Mob. Mut.
6	Lloyd, McCarthy, McGreal and Berry	2003	Business Improvement Districts, Planning and Urban Regeneration [65]	23	Pol. Mob. Mut.
7	Morçöl and Zimmermann	2006	Metropolitan Governance and Business Improvement Districts [82]	22	Urb. Gov. Polit.
8	Mallett	1994	Managing the Post-Industrial City: Business Improvement Districts in the United States [24]	22	Urb. Gov. Polit.
9	Gross	2005	Business Improvement Districts in New York City’s Low-Income and High-Income Neighborhoods [109]	21	Urb. Gov. Polit.
10	Hoyt	2005	Do Business Improvement District organizations make a difference? Crime in and around commercial areas in Philadelphia [73]	20	Impact. Critic.
11	Mitchell	2001	Business Improvement Districts and the Management of Innovation [108]	19	Urb. Gov. Polit.
12	Hochleutner	2003	BIDs fare well the democratic accountability of business improvement districts [110]	19	Impact. Critic.
13	Brooks	2008	Volunteering to be taxed: Business improvement districts and the extra-governmental provision of public safety [77]	18	Impact. Critic.
14	Hoyt	2004	Collecting private funds for safer public spaces: An empirical examination of the Business Improvement District concept [74]	18	Impact. Critic.
15	Levy	2001	Paying for the Public Life [26]	17	Urb. Gov. Polit. Impact. Critic.

¹ Pol. Mob. Mut—Policy Mobilities and Mutation; Urb. Gov. Polit.—Urban Governance and Politics; Impact. Critic.—Impacts and Criticisms.

A second conclusion is that the number of heavily cited studies on policy mobilities and mutation has decreased when compared with the most cited studies in the Scopus database. This trend can be explained by a dual process. On the one hand, some of these recent studies [101,102] are commonly cited on issues that are not exclusively BID-related because BIDs often constitute an illustrative example of broader contemporary processes, such as relational/territorial conceptualizations in policymaking processes. Hence, these studies’ total citations are explained by the innovative conceptualizations they introduce rather than their focus on BIDs. On the other hand, studies on policy mobilities specifically addressing BIDs international transfer were the most cited by other retrieved documents on BIDs [12,28,36].

Finally, studies that examine BIDs’ impacts and criticisms were more highly cited within the core documents included in this review than in the Scopus database. These studies often focus on the US BIDs’ successful stories, having, thus, received extensive academic attention as political legitimization tools to adopt BIDs elsewhere [73,74,77,110].

4.3. Epistemic Communities and Collaboration Networks on BIDs

Author collaboration networks in academic knowledge on BIDs showed low levels of cooperation. In addition to the results showing a low number of collaboration networks with at least two co-authorships, the resulting clusters also indicate that the collaboration index between different epistemic communities is non-existent (Figure 5).

First, authors from cluster 1, to which the most productive author on BIDs belongs, have focused on discussing the relationship between BIDs and regional and metropolitan governance issues within public administration framework, particularly in the US states of Georgia and Pennsylvania. Some of their conclusions indicate that BIDs have become powerful agents in urban governance networks, thus raising accountability issues in the management of these structures [39,78,79,80,81,111]. More recently, this cluster has been analyzing how different states enabling laws can limit BIDs’ role in urban politics, namely through the conception of transparency and controlling mechanisms [112].

Cluster 2 is mainly related to the issues of BIDs’ transfer to the UK [65,67,69]. These studies analyzed the potential of transferring a new form of contractual governance that had proved successful elsewhere and made specific policy recommendations on the need to adapt BIDs within the UK to different legislative, social and institutional contexts [65,69,113]. As in the UK it is each devolved nation that elaborates its own legislative initiative, Peel & Lloyd [67] discussed the main conclusions of the consultation process in Scotland and recommended that a different BID ‘model’—‘community-led model’—was necessary for the Scottish context when compared to the ‘business-led model’ introduced in England and Wales.

While cluster 3 presents a thematic similarity with cluster 2, the former still has an active influence on BIDs literature, particularly in the UK. This cluster is associated with studies that focus on the performance of US BIDs and draws implications that the introduction of these governance structures has for the social and economic vitality and viability of shopping districts in the UK [114]. These studies concluded that former public–private partnerships for the management of town centers—based on voluntary funding mechanisms, including UK Town Centre Management—have performed worse than US BIDs. Thus, these studies recommended the introduction of BIDs in the UK [66,115]. The most productive authors in this cluster have recently extended their collaborative networks to other institutions (BID Foundation and Institute of Place Management), where other academics have closely followed the development of UK BIDs [30].

Cluster 4 focuses mainly on conceptualizations related to policy transfer, mobility and mutation of contemporary urban policies. Shedding light on the rise of entrepreneurial governance arrangements over the last decades [19,70], these studies have examined how BIDs have been disembedded from, and re-embedded into, different contexts based on successfully urban management ‘models’ found elsewhere [28,36,38,91]. Drawing on these studies, a transatlantic cluster has emerged between Canada and the UK. For example, McCann and Ward have argued for a new multi-disciplinary approach to policy transfer that should be sensitive to both relational and fixed dimensions and focused on explaining how and why some policies are mobilized and what these journeys mean for urban politics [101,102]. Within this framework, Cook and Ward [103] discussed how informational infrastructures, such conferences, constitute important relational arenas through which policies are learned and eventually made mobile.

Cluster 5 is mostly associated with studies on the assessment of the impacts of US BIDs, particularly related to crime patterns. For instance, Stokes [116] assessed how BIDs’ services contributed to improving the physical, commercial and security atmosphere of the district. Drawing on debates linking BIDs to privatization of public space and urban governance [117,118], MacDonald et al. [119] found that BID creation led to a reduction in robbery and violent crimes while Cook & MacDonald [106] showed that, in addition to low levels of crime displacement, BID existence resulted in arrests reduction. Similarly, MacDonald et al. [120] concluded that BIDs were positively associated with violence reduction, particularly within their boundaries.

Authors from cluster 6 focus on issues related to the territorialization of BIDs in South African cities. Building on mobility and mutation approaches (cluster 4), this cluster examined how US BIDs were socially and politically constructed as a legitimate model to be imported to Cape Town and Johannesburg within a framework of a neoliberal shift in the post-apartheid political agenda [71,72]. Simultaneously, this critical literature focused on the variegated neoliberalism to discuss the adaptations that the ‘model’ underwent upon arriving in South Africa, suggesting that BIDs are plastic and resilient urban policies that easily adapt to new territorial contexts [83,84,85,86]. This cluster is characterized by international cooperation between French and South African institutions as they share research interests on the privatization of security in South African cities.

Finally, cluster 7 reveals a set of academics that constitute what we might coin as the ‘German School of BIDs’. Similar to clusters 2, 4 and 6, this cluster examines how BIDs were contextualized and transformed in Germany through the lens of policy mobility and mutation [88,121]. These academics discuss how BIDs were constructed in relation to the US and UK and how they ended up being territorialized in Germany [13,88]. This cluster advances BID academic knowledge by arguing that policy failure and resistance should be as carefully examined as ‘successful transfers’ [87,122]. Thus, these scholars have argued that the territorialization of BIDs in Germany constitutes an example of an unsuccessful transfer.

4.4. Towards a Longitudinal Conceptual Framework of Academic Knowledge on BIDs

Drawing on a content analysis technique that uses keyword co-occurrence in the retrieved documents, it was possible to trace the longitudinal evolution of the conceptual structure of academic knowledge on BIDs (Figure 6).

According to the size of the nodes, the keywords that co-occurred most frequently in studies on BIDs were ‘business development’ (34), ‘governance approach’ (33), ‘United States’ (31), ‘urban policy’ (25), ‘urban planning’ (24), ‘neoliberalism’ (23), ‘United Kingdom’ (19), ‘urban development’ (18), ‘South Africa’ (17), ‘urban renewal’ (17), ‘public space’ (17), ‘Canada’ (17) and ‘public–private partnership’ (16). Two conclusions can be drawn from this conceptual network. On the one hand, it reflects the geographic scope where most case study-based research on BIDs has been conducted, which echoes the overrepresentation of Anglo-Saxon countries in terms of scientific production (US, UK, South Africa and Canada). On the other hand, it uncovers some of the main operational features of this revitalization policy. First, BIDs have been conceptualized as an economic development policy (‘business development’) aimed at revitalizing the urban business climate. Thus, strong links between ‘urban economy’, ‘urban planning’, ‘urban policy’ and ‘urban renewal’ were found in this conceptual framework. Second, BIDs have been conceptually described as a new governance framework for urban areas. In addition to a strong connection between ‘urban planning’ and ‘urban policy’, the keyword ‘governance approach’ co-occurred frequently with the concept of ‘neoliberalism’. This indicates that the study on BIDs has been conceptually framed by the progressive involvement of the private sector in urban governance through the enhancement of public–private partnerships other than Town Centre Management (for example, see proximity with the UK).

Moreover, thematic and conceptual shifts in academic knowledge on BIDs were longitudinally identified. Firstly, the first themes (until 2010) focused on the analysis of BIDs as an urban economic revitalization policy and examined their introduction in different contexts, particularly in the UK. BIDs’ impacts and, mainly, the privatization of public space were themes equally debated during this period. Secondly, since the early 2010s, the discussion spread to South African cities where the introduction of BIDs was linked to the embeddedness of neoliberal and entrepreneurial forms of governance. Finally, while policy mobilities approaches were introduced on BIDs in the late 2000s, these epistemological lenses have expanded in recent years due to the increase in scientific production on the territorialization of BIDs both in South Africa (cluster 6) and mainly in Germany (cluster 7).

5. Discussion and Concluding Remarks

This paper has examined the academic knowledge produced on BIDs, an urban and economic revitalization policy set in motion over the last few decades through international policymaking circuits. By mobilizing bibliometric methods and bibliometrix-R tool, we analyzed the temporal and spatial rhythms of the academic literature on BIDs and documented the most influential scholars, sources and publications. Our analysis has also shed light on the making of epistemic communities and discussed those research fronts that have emerged.

In concluding this paper, our findings advance scientific knowledge on BIDs through six fundamental points. The first conclusion is that the BID ‘model’s’ internationalization was accompanied by an increase in scientific production from the early 2000s onwards. While BIDs emerged in Canada in 1970 and scientific production subsequently emerged in that country, it was not until the early 2000s that the academic knowledge on BIDs reached its first scientific production peak. These temporalities echo, first, the rapid expansion of US BIDs in the 1980s and 1990s and, second, the interest of policymakers and academia in the success stories that accompanied some East Coast US BIDs. This policy has been presented as a means of revitalizing downtown cores and town centers in different local settings. Similarly, we have witnessed a successive increase in scientific production on BIDs since the 2010s as we have seen the emergence of this form of local governance in other socio–spatial and political–institutional contexts.

The second point is that the spatialities of scientific production on BIDs—concentrated in the US, UK, Canada and South Africa—disclose the ‘fertile’ political contexts in which BIDs have been formed. These geographies show the unequal role of the state and other private actors’ involvement in local governance and its meaning for the transformation of state-market power geometries and relations in contemporary urban politics. BIDs are an urban and economic revitalization policy that has flourished in contexts where there is history of more entrepreneurial and neoliberal forms of urban governance. BIDs thus draw upon and extend pre-existing patterns.

The third conclusion is that there is a remarkable divergence between scholars and documents with more ‘local’ citations, that is, authors/publications that were only cited in the 239 retrieved documents included in this review, and academics and documents with more ‘global’ citations throughout the Scopus database. While the former includes early works that narrowly examined BIDs’ foundational principles and concepts, their role in urban governance networks and their impacts and criticisms for local governance, the latter comprises more recent papers and authors that draw on policy mobilities–mutations conceptualizations to examine BIDs as an example of a ‘successful’ and ‘mobile’ urban policy that has circulated internationally and has been territorialized in different territorial settings over the last few decades. Thus, the relational/territorial framing that is derived from policy mobilities approaches appears to lie behind the internationalization of the BID academic literature as the scientific influence of some of the most cited authors and documents are not only explained by their performance in the BID literature but increasingly by their contribution to other research areas beyond BID issues. For these reasons, we argue that future research agenda on BIDs should draw upon and extend this framing and engage with two important, yet unexplored, academic debates. First, there is a need for moving beyond the analytical bias towards ‘successful’ BIDs and carefully examining BIDs that underwent territorial resistance and eventually failed. Second, there is a need to examine the micro-local settings in which each individual BID is successfully or unsuccessfully negotiated and implemented rather than strictly focusing on inter- and intra-urban policy pathways.

The fourth point is that there remains further scope for both academics to write to a wider set of non-academic audiences and for non-academics to write in scientific journals. BIDs are an urban and economic revitalization policy that has received little academic attention, despite its broad internationalization to different spatial contexts. While this study has mainly focused on the work generated by academics, it should be noted that some BID practitioners have already published their practical expertise, for example, in the likes of the Journal of Urban Regeneration and Renewal and the Journal of Place Management and Development. However, this still constitutes a relatively small presence in the academic literature on BIDs as practitioners tend to widely share their experiences through other channels, including blogs, technical reports, task forces and other grey literature platforms, rather than through academic journals. For these reasons, future research might usefully draw upon the expertise and knowledge of academics and non-academics and their institutions in co-producing a ‘BID epistemology of practice’ to encourage collaboration between academia and practitioners in theoretical and applied studies on BIDs.

The fifth conclusion is that there are limited collaboration levels across intellectual clusters. While in the 1980s and 1990s the BID literature was largely produced by individual authors and, thus, intellectual interactions were limited, there has been an increase both in scientific production and authorship collaborations on BIDs since the early 2000s. Simultaneously, the epistemic communities have diversified their thematic interests (urban governance/politics, policy mobilities–mutation and impacts assessment and criticisms). However, findings suggest that, while four of the seven main intellectual clusters in BID literature have examined the international circulation of BIDs to different socio–spatial and political–institutional settings, scientific collaboration across these clusters is limited. The overrepresentation of intellectual clusters on BIDs’ transfer, mobility and mutation issues also resonate with the recent conceptual framework that identified these issues as ‘emerging research fronts’. Thus, one possible future research agenda might be to enhance collaboration between intellectual clusters, particularly those focused on the international mobility and mutation of BIDs. Again, and in addition to expanding the conceptualizations around urban policy mobilities debates to which studies on BIDs have contributed, it could be advantageous to bring together inter-clusters experts on trans-local BID expansion as a means to advance academic and practitioners’ knowledge and understand the local urban politics around BIDs territorialization. In particular, future research agenda should shed light on the contextual-based reasons underpinning BID success and failure in different territorial settings and the negotiations, contradictions and tensions that bound up forming and/or delivering a BID.

The sixth point is that future literature reviews on BIDs might be useful. While bibliometric and science mapping methods provide useful information to draw a comprehensive overview of the academic literature on this form of local governance, these techniques are not substitutes for the traditional and qualitative-based literature reviews and are often embedded in methodological glitches. First, further reviews should combine bibliographical data extracted from multiple scientific databases. As BIDs are still a relatively modest, but growing, scientific subject, this choice would ensure greater diversity of publications, including beyond Anglo-Saxon geographies. Second, further reviews should also carefully consider longitudinal changes in the journals indexed in scientific databases to avoid analysis inconsistencies over time. Finally, there is a need for more comprehensive longitudinal and thematic analysis. Do different scientific production temporalities discuss the same issues through the same conceptual and theoretical lenses? What has been discussed on particular issues within the BID literature, such as urban governance and policy mobilities? Are there any conceptual and theoretical differences in how different epistemic communities address those issues? While some questions remain unanswered, this paper attempts to be a point of departure to inform these and further debates on BIDs.