Introduction

In recent decades, the prevalence of children’s mental health disorders has increased (Duong et al., 2021; Perou et al., 2013) with as many as 15–20% of children meeting criteria for a mental health disorder (Polanczyk et al., 2015; Vasileva et al., 2021). Disruptive behavior disorders (DBDs; i.e., oppositional defiant disorder, conduct disorder and attention-deficit/hyperactivity disorder) are among the most common reasons for referral to children’s mental health services (Merikangas et al., 2009). Importantly, there are a wide range of interventions to treat DBDs with a strong body of evidence supporting their effectiveness. Behavioral parent training (BPT), however, has been shown to be the most effective in addressing DBD behaviors and supporting key parenting outcomes (e.g., parenting behaviors and parent stress; Eyberg et al., 2008; Kaminski & Claussen, 2017). BPT is defined as a treatment approach based on social learning theory wherein antecedents (e.g., behavioral requests and establishing rules) and consequences (e.g., labeled praise and time out) of child behavior are systematically introduced and parents are encouraged to practice the strategies with their child between sessions. Though BPTs vary in their specific content, they generally include: (1) a primary focus on the parent as opposed to the child, (2) emphasis on both reduction of problematic behaviors and increase of pro-social behaviors, (3) supporting parents in identifying and recording child behavior, (4) focus on social learning principles (e.g., modeling, contingent attention following desired behaviors), (5) didactics delivered to parents teaching positive parenting skills (e.g., praise, modeling, and reflecting child verbalizations) and regular practice of these skills, and (6) discussion on how to generalize these skills outside of the clinic setting (Kaehler et al., 2016; McMahon & Forehand, 2003; Shaffer et al., 2001).

A longstanding issue in the field of mental health in general, and BPT in particular, has been the lack of full consideration of male-identified caregivers, hereafter referred to as fathers. Father engagement refers to the “mechanisms in place to invite, enroll, and admit” fathers into treatment (Fabiano & Caserta, 2018, p. 849). Given that BPTs were largely developed with mothers (i.e., female caregivers) as the primary caregiver parent in mind, fathers have historically been underrepresented in intervention design, evaluation, and delivery of BPT (Panter-Brick et al., 2014). In fact, a recent study surveying community therapists found that fewer than one in five therapists have cases where fathers are regularly attending sessions for their child clients (Tully et al., 2017). Another recent study of children’s mental health services found that fathers attended significantly fewer parent sessions as compared to mothers (48.18% vs. 92.83%) and that self-referred families were more likely to be mother referred (87.4% mother referred; Dadds et al., 2018). Low father engagement rates persist despite growing evidence that when they engage in positive ways, fathers can have a unique and lasting impact on child development (e.g., Panscofar et al., 2010) and treatment outcomes (Bagner & Eyberg, 2003; Fletcher et al., 2011).

Benefits of Father Engagement on Child Development and Treatment Outcomes

Sensitivity and support from fathers has been associated with positive pro-social relationships and friendships in children and adolescents (Cabrera et al., 2012), and fathers who engage in complex play tend to raise children with superior language development as compared to fathers who engage in less complex play (Malin et al., 2014). Specific to engagement in BPTs, studies including fathers in treatment, compared with those where the father was not included, reported significantly more positive changes in both child behaviors and desirable parenting strategies (e.g., use of praise and consistent follow-through; Lundahl et al., 2008). Father involvement in BPTs has also been associated with maintenance of treatment outcomes at follow-up (e.g., Bagner & Eyberg, 2003). Improved rates of father engagement could help maximize the number of children and families who benefit from the gains from BPTs. Despite these positive outcomes in child development and treatment, fathers continue to be engaged at low rates, potentially in part due to barriers to father engagement.

Challenges to Father Engagement in BPTs

Ample research has documented barriers to father engagement in BPTs (Fabiano, 2007; Panter-Brick et al., 2014), including from the perspectives of therapists providing these services (Klein et al., 2022). These findings have suggested that both research and practice can inadvertently reinforce societal expectations about which caregiver(s) should participate in treatment. These expectations can involuntarily exclude fathers and reinforce gendered expectations of parenting (Cabrera et al., 2018). Failure to challenge these expectations may lead to additional responsibilities for mothers and deny fathers the opportunity to enhance their parenting skills and relationships with their children. In addition to gendered expectations of parents, fathers have demonstrated lower readiness to change their parenting behaviors and find components of BPTs less acceptable than mothers (Niec et al., 2015; Tiano et al., 2013). In general, men also exhibit fewer help-seeking behavior for mental health services (e.g., Addis & Mahalik, 2003). Therapists have noted various challenges engaging fathers, including difficulties with scheduling and availability, differing parental perceptions of child problems, familial gender roles, and aversions to certain aspects of treatment (Klein et al., 2022). Provider attitudes and behaviors may contribute to fathers feeling excluded and unimportant in treatment (Cosson & Graham, 2014; Lechowicz et al., 2019). In addition, several structural barriers to father engagement exist, including scheduling and availability with father work schedules, which may be especially pressing for low-income families (Chacko et al., 2009, 2018; Quetsch et al., 2020; Tully et al., 2017). Although many challenges have been documented, reviews addressing father engagement have also identified potential solutions.

Past and Current Systematic Reviews of Father Engagement in BPTs

Forty years ago, Budd and O’Brien (1982) reviewed the BPT literature and highlighted the low level of father involvement relative to mothers. At the time, the majority of studies did not include fathers and, among those that did, they concluded that including fathers did not lead to more positive treatment outcomes (Budd & O’Brien, 1982). Although father involvement in childcare has increased over the past 50 years (Parker & Livingston, 2017), systematic reviews and meta-analyses over the past few decades suggest that father involvement in BPT has remained low (e.g., Fabiano, 2007; Panter-Brick et al., 2014; Tiano & McNeil, 2005). Even when fathers have been included in BPT studies, data are often reported in a way that makes it difficult to draw meaningful conclusions about factors that may contribute to effective father engagement. For example, multiple reviews found that studies including fathers often do not report and analyze mother and father data separately, precluding efforts to assess factors that may contribute to engagement and positive outcomes for fathers (Fabiano & Caserta, 2018; Fletcher, Freeman, & Matheny, 2011; Phares et al., 2005; Tiano & McNeil, 2005). Although prior reviews have been unable to evaluate the factors that may contribute to father engagement, two meta-analyses suggest that father involvement in BPT has positive outcomes for families. In their review of nine randomized controlled trials of BPT, Lundahl and colleagues (2008) found more positive child and parenting post-treatment outcomes among studies that included fathers compared to those that did not. A more recent meta-analysis found clear, positive effects of BPT for both mothers and fathers; however, though both illustrated meaningful improvements following BPT, the effect size was relatively smaller for fathers relative to mothers (Fletcher, Freeman & Matheny, 2011).

Across reviews, a number of strategies are suggested as possible ways to increase father engagement. Reviews advocate for setting an expectation early in the enrollment process that fathers will be involved in BPT with processes in place to reduce barriers to father participation such as offering flexible hours and childcare and taking a strengths-based approach to supporting the development of effective parenting (Fabiano, 2007; Fabiano & Caserta, 2018; Lechowicz et al., 2019; Maxwell et al., 2012). Consideration of family culture and other contextual factors is also recommended, given that father involvement may not be beneficial in the same manner across families (Maxwell et al., 2012). Other recommendations include staff training in father engagement, ensuring BPT components are relevant for fathers, and ensuring that organizational policies and procedures facilitate father engagement (Lechowicz et al., 2019; Panter-Brick et al., 2014; Pfitzer et al., 2017).

Current Systematic Review

As the field moves from recognizing the problem of low involvement (e.g., Fabiano, 2007; Fabiano & Caserta, 2018; Tiano & McNeil, 2005) to developing solutions that increase involvement in treatment programs, there is utility in the review the research literature to identify potential strategies that have been effective in this regard. The current systematic review is organized around the following aims: (1) document the engagement and attendance of male caregivers in studies of behavioral parent training, (2) evaluate the extent to which behavioral parent training studies incorporate father-specific engagement strategies, including specific interventions or agency-level implementation strategies and (3) report on demographic representativeness of the parent and child samples of studies where fathers are engaged. Aim 1 will provide an update to recent systematic reviews and determine whether engagement rates have improved in recent years. Aim 2 will help researchers and providers understand which engagement strategies or intervention formats may be most likely to improve father engagement. Finally, Aim 3 will highlight whether efforts to engage fathers in BPT have equitably reached diverse samples of fathers. To address these aims, a review of BPT studies for treating Oppositional Defiant Disorder (ODD), Conduct Disorder (CD), and Attention-Deficit Hyperactivity Disorder (ADHD) was conducted, as BPT approaches are considered the most effective treatments for these diagnoses (Evans et al., 2014; Kaminski & Claussen, 2017). Expanding on past reviews, we further focused on intervention, training, and organizational characteristics that were used to promote father engagement in BPT.

Methods

Inclusion and Exclusion Criteria

For the current systematic review, studies had to meet criteria regarding father inclusion, study design, outcome variables, intervention, target problem, child age, and written language of the research study for inclusion. (1) Fathers (i.e., male caregivers) had to be included as participants or targeted specifically by study aims (2) Study designs included in this review were: treatment studies that included comparison of multiple groups or subjects and hybrid implementation/effectiveness studies (3) Outcome variables needed to include a child mental health outcome (4) Interventions needed to be a BPT intervention (5) Target problems needed to be one of the following: ADHD, ODD, CD, aggression, or externalizing problems (6) Child age needed to be under 18, and (7) Language of publication needed to be English. Articles were excluded if fathers were not included as participants or targeted by study aims, if target problems were not ADHD, ODD, CD, aggression, or externalizing behaviors, if the study did not include a child mental health outcome, if the study was not a treatment or implementation study or did not include a comparison group, or if the article was not in written in English. Treatment studies investigating medications were not included.

Search Strategy

We searched PsycINFO and PubMed due to our focus on mental health literature and the search was conducted on April 14th, 2022. Our search strategy included terms related to four main concepts: (1) behavioral training (“behavioral training” OR “behavioural training” OR (behavior AND train*) OR (behaviour AND train*), (2) included diagnoses or presenting problems (ADHD OR “attention deficit hyperactivity disorder” OR ODD OR “oppositional defiant disorder” OR CD OR “conduct disorder” OR aggression OR externaliz*), (3) parents (parent* OR father* OR dad* OR mother* OR mom* OR coparent* OR co-parent*), and (4) terms related to treatment or implementation studies (engagement OR recruit* OR involv* OR retention OR outcome* OR inclusi* OR intervention OR education OR treatment OR “clinical trial”). All articles were then entered into Covidence (2022), an online software developed for systematic reviews, which aids in identifying duplicates and extracting data. Each title and abstract was then reviewed to identify articles meeting inclusion criteria. To ensure reliability in screening, two authors screened each title and abstract. The authorship team met at regular intervals during screening to establish screening consensus, further clarify inclusion criteria, and discuss any discrepant screening decisions with the full team. The full-text of remaining articles was reviewed, with specific attention to the methods section, to thoroughly assess for inclusion criteria. Furthermore, we reviewed the articles that were included in the past reviews of father engagement studies as an additional research report retrieval strategy.

Data Extraction and Coding Procedures

A codebook was created collaboratively with input from all the authors. Included articles were then reviewed and data was extracted using the Covidence web-based software. In accordance with study aims, information was extracted related to rates of father engagement and attendance, use of father-specific engagement strategies, intervention characteristics, agency-level implementation strategies, and child, parent, and family demographics. Qualitative information was collected for use in narrative synthesis along with coded information regarding the presence of specific strategies, for example.

Methods of Synthesis

Based on recommendations for narrative synthesis for systematic reviews, we primarily used tabulation and textual descriptions to summarize the included studies and answer the primary research questions (Popay et al., 2006). Tabulation and textual descriptions were extracted to better understand the intervention and implementation characteristics associated with father engagement (see Table 1). Textual descriptions included writing brief descriptions of engagement strategies related to intervention design, provider training, and organizational characteristics.

Table 1 Summary of articles included in systematic review
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Results

Aim 1: Documenting Father Engagement and Attendance Outcomes

This systematic review identified treatment studies published between 1990 and 2022 that reported on BPT interventions where fathers are included as participants or targeted specifically by study aims. As seen in the PRISMA diagram (Fig. 1), after removing duplicates, 777 abstracts were screened. After full-text review, a total of 19 articles met inclusion criteria, one study was removed as it was a follow-up study, and an additional 8 articles were added from the references of two recent systematic reviews on father engagement (Fabiano & Caserta, 2018; Tiano & McNeil, 2005). This resulted in a total of 26 studies from which data were extracted to complete the current review (see Table 1).

Fig. 1
figure 1

Identification of studies via PsychINFO and PubMed

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In terms of father engagement and attendance outcomes, we found that 15.4% of studies (n = 4) included only fathers as participants. Father engagement, defined as the percentage of fathers who initiated treatment in each study, yielded a wide range of results. A significant proportion of studies did not report father engagement at all or collapsed engagement rates across fathers and other caregivers (34.6%, n = 9). While a small percentage of studies reported 100% engagement (n = 5), the remaining studies (n = 12) reported father engagement that ranged from 3.57 to 97.4%. Roughly three-quarters of studies (76.9%, n = 20) did not report the overall percentage of sessions attended by fathers throughout the course of treatment. Attendance rates were inconsistently reported with some studies reporting percentage of sessions that fathers attended over the course of treatment and others using a percentage of fathers who were considered treatment completers by a specific cutoff determined using idiographic study criteria. Data were extracted on whether fathers were involved as participants in specific ways; in 26.9% of studies (n = 7) fathers had a distinct role in treatment, and in 38.5% of studies (n = 10) father outcomes were analyzed separately.

Aim 2: Father-Specific Engagement Strategies

First, intervention information was extracted to identify potential trends in those with higher rates of father engagement. Interventions included in the current review consisted primarily of evidence-based parenting interventions. The most utilized interventions include Parent Management Training/Oregon (PMT/PMTO; n = 5; Barkley, 1997), Parent–Child Interaction Therapy (PCIT; n = 4; Eyberg & Funderburk, 2011), and Triple P (n = 2, Sanders, 2012). As indicated in Table 1, several studies (15.4%, n = 4) included some form of cultural adaptation to an existing BPT. Interventions listed as Other include Culturally Adapted Evidence-Based Treatment (CAT; Gerdes et al., 2015), and the 4 Rs and 2 Ss Strengthening Families Program (Gopalan et al., 2015), among other evidence-informed BPTs. All studies targeted parenting skills by nature of their design; however, a smaller percentage of studies specifically targeted parenting knowledge (42.3%, n = 11), or co-parenting (19.2%, n = 5).

The only intervention specifically designed for fathers is the Coaching Our Acting-out Children: Heightening Essential Skills (COACHES; Fabiano et al., 2001) intervention, which was highlighted in several studies within the current review (11.5%, n = 3). COACHES is unique in that it incorporates fundamental parenting skills but delivers them in the context of recreational activities for fathers and their children. The intervention utilizes common positive parenting skills (e.g., praise, reinforcement, and time-out) but offers fathers the opportunity to implement them in the context of soccer drills and games. Brief breaks during games are held where facilitators ask fathers to identify skills they used during each section of the game in order to reinforce learning and skill use. Similar to many other BPT approaches, homework is assigned weekly in order to generalize skills to other settings.

Next, data were extracted on which father-specific engagement strategies were used to recruit, retain, and enhance outcomes for fathers. The vast majority of studies included in the current review (69.2%, n = 18) did not describe any specific father engagement strategies used within the design or implementation of the interventions. Of the studies that did describe father engagement strategies used (n = 8), the most common strategy used was altering the treatment format or content to address father-specific parenting concerns (n = 5). A primary example of this type of father engagement strategy is the COACHES intervention (Fabiano et al., 2009, 2012a, 2012b, 2021), where intervention format was altered to include recreational activities as the in-vivo context for parenting skill implementation. Frank and colleagues (2014), modified treatment content to include an explanation of the benefits of father engagement on child development, strategies for managing father-specific parenting challenges (e.g., co-parenting, balancing work and parenting responsibilities), and father-identified areas of interest (e.g., improving child social skills; Frank et al., 2014). Finally, Stolk and colleagues (2008) modified an intervention designed for maternal sensitivity to invite fathers to two booster session; however, only 21% of fathers attended both sessions.

The second most common father engagement strategy was a change in physical treatment setting (n = 4). This most frequently occurred through the COACHES intervention which utilizes a recreational treatment setting through a clinic (Fabiano et al., 2009, 2012a, 2012b) or school (Fabiano et al., 2021). Another study utilized a father-only delivery of the Incredible Years (Webster-Stratton & Hammond, 1997) delivered within Head Start school settings intended to reduce transportation barriers (Helfenbaum-Kun & Ortiz, 2007); however, this study reported low rates of treatment completers (30%). Two studies reported reducing the length of treatment by shortening the intended number of sessions for all parents to create a brief intervention model. In both cases, this was done without compromising intervention effectiveness (Fabiano et al., 2021; Gopalan et al., 2015). Lastly, one study explicitly lowered the treatment expectation for fathers and working parents, allowing them to attend every other session as opposed to maintaining an expectation that all caregivers are engaged throughout the entire intervention (Parra-Cardona et al., 2017).

Finally, information regarding treatment setting was extracted to provide context as to agency-level implementation strategies that may improve father engagement. The interventions were delivered in a wide range of settings with the most common being traditional outpatient clinics (26.9%, n = 7), community mental health settings (19.2%, n = 5), and schools (15.4%, n = 4). Other settings included university training clinics (n = 4), foster care settings (n = 1), in-home settings (n = 3), and telehealth (n = 1). Five studies (19.2%) included a combination of two settings and an additional five studies (19.2%) did not report agency or clinic settings. Apart from studies that utilized the COACHES intervention (n = 3), which specifically trained providers on how to engage fathers through recreational delivery of parenting skills, no father-specific policies were implemented at an agency level.

Aim 3: Child, Parent, and Family Demographic Characteristics

Child, parent, and family demographics were collected in regard to age, gender, diagnosis, and race/ethnicity. Limited information was also collected regarding family socioeconomic status or family income. The average age of children in treatment was 7.54 years and were predominantly male in terms of gender (71% on average). The most common presenting concern for children in treatment was externalizing problems (34.6%, n = 9), followed by ADHD (26.9%, n = 7), ODD (23.1%, n = 6), CD (7.69%, n = 2), and aggression (3.85%, n = 1). Two studies (7.69%) were categorized as “Other” as they targeted conduct problems generally. Child race/ethnicity was reported in 50.0% (n = 13) of studies. One study (Gopalan et al., 2015), which specifically targeted families of diverse racial/ethnic backgrounds, enrolled child participants that were 29.7% black, 48.8% Hispanic/Latinx, and 9.4% Other (e.g., biracial/multiracial). Another study enrolled 100% Asian/Pacific Islander children as it was specifically targeting Burmese families (Annan et al., 2017). The remaining studies that reported on child race/ethnicity (42.3%, n = 11) enrolled predominantly Non-Hispanic White children with percentages ranging from 70.5 to 100% of child participants.

Parent or caregiver race/ethnicity was reported in 38.5% (n = 10) of studies. Similar to child demographics, one study that targeted Burmese families included 100% Asian/Pacific Islander parents (Annan et al., 2017), one study which took place in community settings had a majority representation of Black/African American parents (38.9%; Acri et al., 2022), and several (n = 4) studies tested cultural adaptations for Latinx families or targeted Head Start families where the majority of participants were from Latinx families (85–100%; Gerdes et al., 2021; Helfenbaum-Kun & Ortiz, 2007; Knox et al., 2011; Parra-Cardona et al., 2017). The remaining studies that reported caregiver race/ethnicity (n = 4) were predominantly Non-Hispanic White with percentages ranging from 64.0 to 93.2% of parent participants. Parent age was, on average, 35.5 years for mothers and 39.6 years for fathers. Parent gender was only reported as male or female for all included studies.

Socioeconomic status was inconsistently reported with a wide range of measurement tools used in the existing descriptions. Two studies using the Hollingshead Four Factor Index (Hollingshead, 1975) reported an average score of 30.9 indicating lower middle class SES. One study reported an average household annual income at $39,432. Two studies reported the percentage of families enrolled that fell below a particular income level. Specifically, this included 90.5% of families receiving less than $35,000 annually (Helfenbaum-Kun & Ortiz, 2007), and 73.0% of families receiving less than $15,000 annually (Knox et al., 2011). Of the remaining studies which reported SES, several (n = 5) used educational level or employment status to capture a proxy of SES and reported that participants were generally employed and had moderate to high levels of education (e.g., Bachelor’s or above).

Discussion

This systematic review expands on previous reviews of father engagement (Fabiano & Caserta, 2018), to update rates of engagement and attendance and describe how different intervention characteristics and engagement strategies may impact father engagement in BPTs for children with disruptive behavior disorders and ADHD. Engagement, that is whether a father initiates and continues with a behavioral parent training program, is a critical area of study, given that prior reviews have indicated fathers of children with disruptive behavior disorders are less likely to participate in parent-focused interventions, relative to mothers (e.g., Fabiano, 2007; Tiano & McNeil, 2005). Each of the major results of this systematic review will be addressed, in turn, followed by a discussion of potential future directions for research and intervention.

While many studies in the current review failed to report on the percentage of fathers that completed treatment, it should not be overlooked that a select few did achieve marked success in fathers attending and completing treatment. Among them were two studies which utilized the COACHES intervention (Fabiano et al., 2009, 2012a, 2012b), an intervention that incorporates father–child sport activities into the intervention format and has been able to enhance positive parenting skills by pairing play with behavioral parent training. This change in the treatment setting responds to previously reported barriers in accessing traditional clinic approaches (Klein et al., 2022). Further, COACHES avoids a father-deficit model and places more of a focus on the parent–child relationship and child behaviors as intervention targets; this may be well suited for fathers given male hesitancy engaging in help-seeking behavior (Addis & Mahalik, 2003) and their tendency to have positive self-evaluations of their parenting skills (Fabiano, 2007). Notably, two of the three studies utilizing the COACHES intervention achieved father attendance rates above 75%.

Another study, conducted in foster care setting and utilizing intensive, in-home PMTO, reported that 71% of families had both parents engage in treatment (Maaskant et al., 2016), again suggesting that treatment setting may be important. Finally, van den Hoofdakker and colleagues (2014) reported 81.7% of father attendance in their study which found that BPT is most helpful in reducing child behavior problems when their fathers have high levels of ADHD or high levels of parenting self-efficacy. While this study did not employ any targeted father engagement strategies, measuring paternal moderators of treatment outcomes may prove beneficial in future studies. Finally, Webster-Stratton (1996) achieved father attendance rates of nearly 90% in a study that compared child outcomes across combinations of child, parent, and teacher training interventions. Despite most families included in this study being two-parent households where caregivers were married, measures were also consistently collected from both participating parents. While future research would benefit from more thorough meta-analyses to identify predictors of father engagement associated with specific strategies and study designs, it is important to highlight the trends among studies that achieved such successes.

Evidence-based treatment reviews have moved from identifying specific brands of behavioral parent training to a review of the characteristics of effective treatments (Kaminski & Claussen, 2017; Pelham & Fabiano, 2008). In this systematic review, although a number of different formats of parent training were identified (e.g., PCIT, COACHES, and Triple P), the majority included the standard parenting content that included increasing positive parent–child interactions, addressing the antecedents of appropriate behaviors (e.g., establishing rules and structure), and teaching fathers how to implement effective consequences for behavior (e.g., labeled praise and time out). The articles reviewed did not provide sufficient information to judge whether there were particular content items that were more or less effective for fathers, something that warrants further research given the Fletcher et al. (2011) findings that Triple P outcomes were attenuated for fathers, relative to mothers. There was also insufficient study of components of intervention that may impact engagement across studies to yield stable conclusions. One example of this is the inclusion of the child in the intervention, versus father attendance alone. Fabiano et al. (2009) randomly assigned fathers to COACHES, where there was shared parent–child sports activity following a behavioral parent training program, and this was compared to a group where fathers attended the parent training without any shared child activity. Results illustrated improved attendance, on-time arrival, and homework completion for the group that included father–child interactions in sports. As the literature extends from tests of efficacy, to more nuanced questions about how to best engage fathers in treatment, additional studies of strategies to promote engagement and retention are needed. This may be achieved by sequential multiple assignment randomized trials (Almirall et al., 2012; Nahum-Shani et al., 2012) to explore the sequences of approaches that initially engage fathers, and then for fathers who do not initially attend behavioral parent training, what strategies might be effectively implemented next to promote engagement for these fathers (see Pelham et al., 2016 for a related example of this method for assessment treatment engagement and outcome in children with ADHD).

This review sought to expand our understanding of the provider and agency related factors that promote father engagement; however, very few studies described implementation considerations specifically focused on enhancing father engagement. An important finding from this review is that nearly a third of studies occurred in clinic settings. Clinics have traditionally been a setting where father engagement was poor, similar to evaluations of father engagement in school settings (e.g., McWayne et al., 2013). Over the last few years, with forced changes in practice due to the COVID-19 pandemic, telehealth has been increasingly used and accessed as a mechanism to deliver interventions (Koonin et al., 2020). This is an area that holds promise for father engagement (Piotrowska et al., 2020), as prior work has identified travel to a particular location during prescribed hours to be a barrier for fathers (Fabiano, 2007), and an additional barrier was a preference for mothers to want to avoid attending treatment sessions together with non-residential fathers (Fabiano et al., 2016). Culturally responsive telehealth interventions also show promise for diverse children and families, which may accelerate the diversification of fathers engaged in treatment as well (Willis et al., 2022). Telehealth provides greater flexibility for father access to treatment providers in school, clinic, and pediatric settings, and future research should focus on this approach to increasing engagement, as only one study in this systematic review addressed it. Finally, this review points to limited research on how clinicians are trained to engage fathers in BPTs, which could lead to improved competence and confidence in working with fathers (Burn et al., 2019; Klein et al., 2022). Beyond training the providers, organizational approaches (e.g., hours offered, promotional materials, and varied settings for treatment implementation) are needed to enhance father engagement.

Although there have been continued calls for the increased study of father involvement in the behavioral parent training literature for decades (Cassano et al., 2006; Fabiano, 2007; Fletcher, Freeman, & Matthey, 2011; Lee, 2006; Lee & Hunsley, 2006; Phares, 1996; Tiano & McNeil, 2005), one major finding of this review is that the evidence for father involvement, engagement, and treatment outcomes is still lagging behind that of the larger literature on mother-focused parent training outcomes. Historically, the literature on BPTs predominately includes parents and children that are not representative of the population of families that can potentially benefit from parent training interventions, with the majority of research participants (i.e., fathers) being white, in their late-30s (see also McWayne et al., 2013), and middle class or higher. Our review was limited by fewer than half of studies reporting on race and ethnicity, though it was encouraging to see an increased number focused on interventions targeting low-income, families of color (Gopalan et al., 2015; Acri et al., 2022; Gerdes et al., 2021; Helfenbaum-Kun & Ortiz, 2007; Knox et al., 2011; Parra-Cardona et al., 2017). Children in the studies were an average of 7 years old. These findings illustrate numerous limitations of the current research literature that prevent generalizations about best practice approaches. Given the importance of exploring how particular evidence-based treatments, such as BPTs, are received by and work for parents of different cultural or educational backgrounds, the lack of diversity within the fathers included within the BPT literature is of concern and in need of urgent attention. While more demographic information of research participants are warranted, the same is true for the recruitment of diverse fathers and families into research. Nuance is warranted when seeking to engage diverse fathers who, by recent provider reports, may have culturally bound gender and parenting norms that impact their conceptions of treatment (Gonzalez et al., 2022). Community-engaged research methods may be of interest to researchers who seek to engage diverse communities as these methods historically center issues of social justice and strive to uplift the voices of multiple stakeholders (Wright et al., 2020).

Limitations

This systematic review has several limitations. First, the majority of the parenting literature, including the father engagement literature in the current review, remains largely heteronormative, systematically excluding a wide range of gender-diverse, trans, and same-sex parents (Letiecq, 2019; Weeland et al., 2021). Second, it is possible that the research literature search and retrieval process may have omitted relevant studies. Third, due to the focus on studies that evaluated BPT for disruptive behaviors, the results and conclusions may not generalize to BPT focused on supporting children with internalizing disorders. Due to the relatively small number of studies reviewed, and the heterogeneity of reporting across studies, it was not possible to generate estimates of effect size for specific engagement approaches or to conduct any meta-analyses. Additional methodological limitations include the lack of pre-registration in PROSPERO. At the present time, it appears that the literature is still in need for focused, systematic evaluation of engagement strategies to promote male caregiver participation in BPT. As Table 1 illustrates, many studies did not include sufficient information on father engagement and attendance, resulting in a reduced ability to synthesize findings across empirical studies.

Future Directions

Fathers clearly make a unique and important contribution to multiple aspects of child development, and they are an important member of the treatment team supporting children and adolescents with disruptive behavior disorders. The present review illustrates an increasing collection of empirical articles that have explored strategies to engage fathers in BPT, but the research literature is still relatively modest, relative to the overall BPT research literature. Multiple reviews have now been published to highlight the need for additional research on fathers. Yet, when large studies have been done to explicitly include fathers (e.g., Avellar et al., 2011), so few have enrolled that it was not possible to generate meaningful conclusions regarding the efficacy of the parenting and family interventions. Our current review illustrates that the lack of data on father engagement and tailored treatment continues to be modest, at best (see Table 1). Future research would benefit from more detailed and clear description of the father-specific engagement strategies used in treatment to support eventual empirical tests of which strategies lead to improved rates of engagement.

Rather than continuing to “admire the problem” the current findings suggest that future research may benefit from stepping back from tests of efficacy for father involvement in BPT to more basic questions of how to motivate fathers to engage in parent training, given emerging evidence that fathers view parent training intervention initiation and larger treatment efforts in a different way relative to mothers. For instance, Niec et al. (2015) reported in a study of motivation to initiate parent training that mothers were significantly more likely to rate themselves as ready to start treatment. When a readiness-to-change questionnaire was administered to fathers, they were more likely to report no contemplation to change, which would explain a lack of engagement in treatment initiation. Cunningham et al. (2008) also reported that significantly more mothers than fathers were classified as in the category of ready for action. In this study, fathers were more likely to have a more cautious or impaired approach to treatment as they reported they were either interested in more information or overwhelmed. These studies illustrate that mothers and fathers, even within the same family, may have different feelings about treatment, different motivations regarding treatment initiation, and this may result in varied approaches to treatment initiation. Thus, future studies should evaluate initiation to treatment independently as well as jointly for mothers and fathers.

In addition to addressing issues of initial and independent engagement, efforts to reach racially and ethnically diverse fathers and families are needed. The current review highlights the results of a small number of studies targeted towards diverse families; however, the BPT literature remains largely white in terms of its demographics (McWayne et al., 2013). Efforts to recruit, engage, and retain diverse fathers should also systematically consider the ways in which culturally bound gender and parental norms may impact provider and agency efforts. For example, in a recent investigation of lay provider perspectives on engaging Latino fathers, despite feeling that father engagement was largely important, many providers reported culturally bound gender norms impacted their success in engaging fathers (Gonzalez et al., 2022). Further, a culturally adapted PMTO program for Latino families recently reported retention rates for Latino fathers above 80% (Parra-Cardona et al., 2017), illustrating the power that culturally informed practices can have not only in diversifying the families we serve, but in ensuring their success in treatment. These examples are critical to understanding how best to diversify the fathers that we engage; cultural conceptions of fathering should be integrated into our intervention design and implementation. Community-engaged research methods may allow for our intervention design and adaptations to best take into consideration the needs of diverse community members (Wright et al., 2020).

As outlined above, male caregivers make important and unique contributions to child development. The current systematic review clearly indicates that prior concerns about low levels of father involvement in BPT studies (e.g., Fabiano, 2007; Tiano & McNeil, 2005) continue within the research literature, with notable exceptions (e.g., Fletcher et al., 2011). As the field moves forward, this review serves as a repeated call to continue to study the role of male caregivers in treatment studies for children with externalizing behavior challenges. Further, outside of tests of efficacy, future research should recruit diverse samples and explore specific mechanisms to promote engagement and retention of fathers in BPT (e.g., fewer than a third of studies in the present review included father-specific engagement strategies), including how to train clinicians and change organizational policies to include fathers. By focusing on specific strategies to enhance father engagement and BPT outcomes, improvements in family functioning and child behavior may be realized.