Contribution and Trend to Quality Research — a literature review of SERVQUAL model from 1998 to 2013

Ya Lan WANG 1, Tainyi LUOR1, Pin LUARN2, Hsi Peng LU2 1 Graduate Institute of Management, School of Management, National Taiwan University of Science and Technology, Taipei, Taiwan, R.O.C 2 Department of Business Administration, National Taiwan University of Science and Technology, Taipei, Taiwan, R.O.C carol_yl_wang@yahoo.com.tw, dr.luor@gmail.com, luarn@ba.ntust.com.tw, hsipeng@cs.ntust.com.tw


Introduction
SERVQUAL is the abbreviation used for "Service Quality."The SERVQUAL scale was developed based on the ten requisites of quality service in "Conceptual Model of Service Quality-PZB Method" [1].In 1988, PZB conducted further research [2] and categorized their findings into five determinants: Tangibles, Reliability, Responsiveness, Assurance, and Empathy as the SERVQUAL scale.It provides a complete scoring system to every industry, to assist management with credibility and efficiency, and to serve the purpose of service improvement.This study differs from traditional literature reviews.Traditional reviews design SERV-QUAL scales according to the PZB model and measure the clients' satisfaction of service quality.Our research aims to generalize and probe changes in the research on service quality and the areas of analysis over the past fifteen years (from 1998 to 2013), and to serve as an overview to researchers interested in service quality [3].When choosing references, most researchers value the impact factor as an influential criterion in addition to research methods and theories.We use the ISI WOS database as our major research tool.The ISI WOS database collects all recent papers in the Sciences Citation Index (SCI) and Social Sciences Citation Index (SSCI).The metrics for assessing research contribution for academics, departments, journals, and conferences usually have two dimensions: quantity and quality.The quantity can be measured by the number of related publications while the quality can be measured by the number of citations of the papers [4].A metric that combines quantity and quality into a single number called Hirsch Index has been proposed to measure contribution of a researcher [5].We analyze past SERVQUAL articles with four major perspectives: time (number of articles published and times cited each year), geography (country and research institution), productivity (researchers and journals), and impact (number of citations, research fields, and article characteristics) in preparation for future research.This paper is organized as follows: we discuss our research methods with the scope of study and the metrics of research contribution.The results are presented and discussed based on different factors.We conclude our paper with trends that correlated to our re-DOI: 10.12948/issn14531305/19.1.2015.03sults and future work.

Research Methods
In this Section we present our research methods with the scope or our research, and metrics for research contribution.

Scope of the Study
Our study uses keywords to search the ISI WOS database.It includes 367 SERV-QUAL model related articles in 167 SCI and SSCI journals.The result shows that there is an increasing interest in the area of service quality (Figure 1).In particular, the number of articles and the number of citations suddenly increased between 2009 and 2011.Since then, the number of articles on the follow-up discussion regarding this topic has dropped marginally but the times cited have increased.Thus, it can be seen that service quality remains a significant research area among service-related articles.

Assessment of Research Contribution
Quantity and quality of research articles are both important metrics for measuring research contribution.We calculate the number of SERVQUAL articles and times they are cited from the ISI WOS database to measure the "contribution" of authors and articles published.Times cited is a crucial index in measuring contribution of the articles, while the number of articles can reflect important trends in the relevant research, which helps generate value for study and research [6].By generalizing and analyzing their emphasis, we can see (1) the productivity of the journal and the author, (2) the updates of publications as the reference for research expansibility, and (3) the impact on the field by the times cited of the author.

Research Results
The following shows our surveys on SERV-QUAL model by research field, journal, country, institution, researcher, number of citations, and article characteristic.

Frequency of the Research on SERV-QUAL Model by Research Field
We analyze the research fields of the articles (Table 1).According to the ISI WOS database, there are 46 different fields.The articles investigated might overlap across multiple fields.The first five items of the top ten fields cover peoples' lifestyles, core topics of corporations, and life trends.Among these, the most discussed field is the MANAGE-MENT field.The information age also results in the rapid development of e-commerce and related technologies.It not only helps innovation in service values, but also brings about changes in business models.Corresponding-DOI: 10.12948/issn14531305/19.1.2015.03ly, it is also influential in customer satisfaction.Whether this can be converted to profits for companies has been a topic of discussion for many recent papers.Even traditional industries are participating in service quality initiatives, and are no longer using production and yields to measure performance.In general, the number of times cited in the top ten fields can indicate changes in peo-ple's overall attitudes towards life and value systems.For instance, an emphasis on health leads to the popularity of the leisure and tourism industry, in which the customers also value service quality.Throughout all the research fields, we can also see the diversity of articles.

Frequency of Research by SERV-QUAL Article Characteristic
In this Section we look into the article characteristics of the studied SERVQUAL papers.Table 7 describes these characteristics and their definitions [6].We analyze all the studied articles, classify them into five categories and list the top 30 according to the times cited of the articles in SERVQUAL model (Appendix A).We also sum the number of articles from different years according to different categories (Table 8).
The most common type of article is EMPIR-ICAL, where most articles would use SERVQUAL scales to measure the determi-nants of service quality, which is indicated by the questionnaire analysis of the five determinants of PZB.This not only measures client satisfaction but also applies the SERVQUAL model to measure the staff's understanding of service quality to serve the purpose of service improvement.Some scholars propose that the use of this scale should be improved according to different industries so that customers' needs are better perceived.For the articles in the REVIEW category, which are not in the top 30, they can be viewed as being representative of the total picture of SERVQUAL research by scholars, as is this paper.DOI: 10.12948/issn14531305/19.1.2015.03

Table 1 .
The Top Ten Categories According to Numbers of WOS Articles(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) 3.2 Frequency of the Research on SERV-QUAL Model by Journal, Country, Institution, and ResearcherThe top ten journals of SERVQUAL publications are shown in Table2.There were 367 articles published in 167 journals (in ISI WOS database), 140 articles (39%) of which are in the top ten journals.There is an emphasis on articles in the service categories in the practical application and research areas.This emphasis is constant over time and articles have been published and discussed in several professional areas.

Table 2 .
The Top Ten Journals of SERVQUAL Publications (1998-2013) US and Europe remain the leading countries on SERVQUAL model re-search.It also shows three Asian countries (Taiwan, China and South Korea) have 93 (25.3%) articles in total, indicating the significant contribution and interest of Asia in this field.
The top ten countries with the most SERV-QUAL publications are shown in Table3.A total of 52 countries were involved in the publication of articles; 305 (82.3%) articles are from the top 10 countries, while the remaining 17.7% are from the other 42 coun-DOI: 10.12948/issn14531305/19.1.2015.03tries.

Table 3 .
Top Ten Countries of SERVQUAL Publications (1998-2013)We analyze the SERVQUAL articles by active research institution, There are 446 institutional contributions, with 14.4 % of these coming from the top ten institutions.The re-sult is shown in Table4.We find that the result by research institution is consistent with the result by country.

Table 8 .
Number of Articles Based on Article Characteristic of the Top 30 Most Cited METHODS 56 15.Zhu, F. X., Wymer, W., and Chen, I. (2002), "IT-based services and service quality in consumer banking," IN-EMPIRICAL 55