Effect of Pipelines on Enrollment of Underrepresented Students in Healthcare: A Systematic Review : Education in the Health Professions

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Review Article

Effect of Pipelines on Enrollment of Underrepresented Students in Healthcare

A Systematic Review

Tombers, Nicole; Bauer, Joe; Boraas, Aaron; Lundberg, Jordan; Pfeifer, Rachel; Reinartz, Cassidy

Author Information
Education in the Health Professions 6(1):p 1-7, Jan–Apr 2023. | DOI: 10.4103/EHP.EHP_29_22
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While the healthcare workforce has representative diversity on the whole, racial and ethnic minorities are overrepresented among entry-level, lower paying jobs and underrepresented among higher skilled, higher paying diagnosing and treating professions.[1,2,3] Increasing the representation of racial and ethnic minorities is a topic of interest and focus for many health professions.

There are many reasons why representation of providers across racial and ethnic groups is important at all levels of healthcare. Perhaps most importantly, patient–provider concordance in terms of race or ethnicity, language, and other sociocultural characteristics improves patient experiences and health outcomes.[4,5,6,7,8] Providers who are members of underrepresented minority (URM) groups are also more likely to serve minority populations, thereby increasing access to healthcare for underserved and underinsured patients.[6,7,9] A third commonly cited reason for working towards improving representative diversity in healthcare is that it is simply the right thing to do. There is a general expectation that the healthcare workforce will be reflective of the population that it serves.[10] Furthermore, the whole community benefits from having a representative workforce as it reduces barriers to quality care for all members and fosters greater cultural humility among providers.[6,11]

In order to increase representation in the workforce, there must first be improved racial and ethnic diversity within professional education.[12] Among other methods, pipeline programs have been recommended as a means to recruit and retain minority students into healthcare education programs.[6,7,8,13,14,15,16,17] There is no standard definition of what constitutes a pipeline program. They generally involve some allocation of resources and services that target individuals from particular disadvantaged groups with the goal of providing support, improving equity and ultimately bringing them through to matriculation and graduation.[7,18]

Current literature related to pipeline programs primarily consists of case studies and government reports. Currently, there is no literature evaluating the overall efficacy of pipeline programs in making meaningful improvements to representation within professional healthcare education programs. This systematic review aims to evaluate the efficacy of pipelines within individual professional healthcare education programs so that further recommendations in the pursuit of pipelines can be made.


Search strategy

A systematic literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.[19] This review was prospectively registered with PROSPERO under ID CRD42021281463. The authors searched eight databases (CINAHL, Medline, Nursing and Allied Health Premium, OVID, ScienceDirect, Education Index, Proquest, and Google Scholar) in October 2021 in consultation with a librarian. No restrictions on publication date were imposed on the search. Reference lists of relevant review articles and the included studies were hand searched to identify additional studies. The search terms and strategy for Medline were as follows: “Pipeline” [MeSH] AND “Healthcare” [MeSH] AND “Diversity” [MeSH].

Eligibility criteria

Studies investigating the effect of a pipeline on enrollment of URM students within an individual graduate level clinical healthcare program in the USA were included. Due to limited agreement in the literature as to what constitutes a pipeline program, any that self-identified as such were included in this review. Studies evaluating underrepresented students within a pipeline who went on to be enrolled somewhere other than the institution in question, studies on institutions outside of the USA, and studies which did not report both pre- and post-intervention data were excluded.

Study selection

A total of 2228 articles were identified through database searching, with 1524 remaining after duplicates were removed. Of those, 1407 were excluded as they did not fit the inclusion criteria based on title and abstract reviews. The remaining 118 were evaluated through review of the full text. Based on the criteria listed above, five were ultimately included in this review. Two of the present study’s authors independently reviewed articles at each stage of the process. Any disagreements were resolved by a third author who served as a tie-breaker. The selection and review processes are summarized in [Figure 1].

Figure 1:
PRISMA flowchart for selection of studies in the systematic review. PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-analyses


The primary outcome of interest was the percentage of URM students enrolled in a cohort. Where the number of URM students enrolled and cohort size were reported, percentage calculations were made by the authors. Additional data extracted included the profession of the healthcare program, student entrance point into the pipeline and interventions used in the pipeline. In studies where data were presented in a format such that percentages of cohort size could not be obtained, or only post-intervention data were reported, authors were contacted a minimum of two times in order to obtain relevant data. If no response was received after two attempts or necessary data was not available, those articles were excluded.

Risk of bias

Due to the pre-post nature of the studies included in this review, the inevitable lack of randomization in such studies, and the absence of control groups, the Cochrane Risk of Bias tools which would typically be used in a systematic review, were deemed to be inappropriate in this case. Therefore, study quality was assessed using the National Institutes of Health Quality Assessment Tool for pre-post studies with no control group.[20] This tool consists of twelve questions and was “designed to help reviewers focus on the key concepts for evaluating the internal validity of a study” and “not intended to create a list from which to add up items to judge a study’s quality”. For any aspects of a study that are found to have risk of bias based on the questions presented in the tool, reviewers are then asked to consider whether or not it could “lead to doubt about the results reported in the study or doubt about the ability of the study to accurately assess an association between the intervention or exposure and the outcome”. Data extraction and risk of bias assessments for each study were performed independently by two of the present study’s authors, with disagreements settled by a third author who served as a tie-breaker.


Study selection

In total, five studies published between 1999 and 2010 were included in this review.[21,22,23,24,25] These included data from nineteen graduate-level healthcare programs, three of which were medical schools and sixteen of which were dental schools. One article (Brunson, et al.[21]) reported data from fifteen distinct institutions. Each of the other included articles reported on data from a single institution. A breakdown of study characteristics can be found in [Table 1].

Table 1:
Included study characteristics


Following initiation of a pipeline, fifteen health profession education programs reported increased enrollment of URM students, three institutions reported decreased enrollment, and one institution reported no change. Pre- and post-intervention enrollment numbers can be found in [Table 2], with the percent change depicted in [Figure 2]. The time between the reported pre- and post-pipeline intervention outcomes ranged from one to eleven years, with only one study reporting outcomes for each of the interim years.

Table 2:
Percent change in enrollment of underrepresented students in a cohort, with pre- and post-pipeline intervention totals
Figure 2:
Percent change in enrollment of underrepresented students in a cohort from pre- to post-pipeline intervention

Study characteristics

Sixteen of the healthcare education programs welcomed students into a pipeline at the undergraduate level, two welcomed students at the high school level, and one welcomed a combination of high school and under­graduate students. Common components incorporated in the pipelines are shown in [Figure 3] and included the following: mentorship (n = 19), academic assistance such as providing personal tutoring and advanced coursework, as well as instruction in improved study skills and test taking strategies (n = 18), application assistance such as pre-application guidance and interview practice (n = 17), financial assistance such as merit and need-based scholarships and loans (n = 16), priority admission (n = 2), and social support and advising once admitted to the program (n = 3). Some programs had additional optional experiences for students in the pipeline such as summer research experiences, clinical shadowing and community service.

Figure 3:
Number of pipelines that included the stated components

All five studies were found to have poor quality evidence for drawing associative conclusions on the efficacy of pipelines in increasing enrollment of URM students. This was largely due to studies’ lack of statistical analyses of the power and significance of outcomes, as well as a lack of clarity and consistency in how the interventions of the pipeline programs were delivered [Table 3].

Table 3:
National Institutes of Health quality assessment results


The aim of this review was to evaluate the efficacy of pipelines in increasing enrollment of racial and ethnically underrepresented students into graduate-level healthcare education programs. Most health profession education programs included in the present study reported an increase in the percentage of URM students enrolled in a cohort following the initiation of a pipeline. There were three dental education programs that reported decrease in enrolled URM students post-pipeline. In considering potential reasons for this, the article cited a loss of key administrators of recruitment for the pipeline. They also pointed to fluctuations in numbers from year to year and cited increased enrollment in the interim years between introduction of the pipeline and the time at which outcomes were reported four years later.[21]

There are varying arguments in the literature as to the best time to bring students into a pipeline. Consistent with what has been found in the descriptive literature related to pipelines, the studies included in this review onboarded students into the pipeline at either the undergraduate or high school levels.[6] Initiating students in high school has the benefit of exposing those from minority groups to the various career options within healthcare and giving them the time and support to explore their interests in a way that they may otherwise not have an opportunity to do.[16,26,27] Initiation at the undergraduate level may be favored as it captures students who are closer to the point of making decisions about their future education and career.[6,16]

Pipelines that have been described include a wide array of experiences, opportunities, and support.[7,18] Often there are multiple components included in a single pipeline. Several common themes were seen in the studies that were included in this review, and are consistent with those that have been seen in the descriptive literature. Mentorship, academic support, and application assistance are commonly included as part of a pipeline, and may offer the lower barrier to entry for those considering starting a pipeline as they do not require an overhaul of policies, admissions procedures, or financial resources. Other components that are often incorporated into pipelines, and were seen in the studies included in this review, are financial support such as scholarships, grants and loans, priority admission, and additional opportunities related to research or clinical field experience.

The heterogeneity among pipelines, the inconsistency with which they are regularly applied and the current lack of studies having multiple arms to tease out differences between specific components makes identification of the most effective pipeline interventions difficult to isolate.[27] In practical terms, the components that are feasible based on resource availability or that are most successful will likely be specific both to the institution and the targeted minority group.


There are several limitations to this review, including (1) homogeneity of the types of health professions included, (2) low quality of evidence with unclear significance, (3) lack of long-term outcome data, (4) lack of clarity and consistency in the application of the pipeline intervention, and (5) age of the included studies.

The studies included in this review were from medical and dental education programs only. There is a notable lack of studies reporting on outcomes from pipelines across the range of diagnosing and treating professions. This makes the generalizability of our results difficult. Further research should include an evaluation of the impact of pipelines on racial and ethnic representation in other allied health profession education programs such as physical therapy, occupational therapy, speech therapy, respiratory therapy, and advanced practice nursing.

None of the studies in this review evaluated or reported the significance of the changes to enrollment rates of URM students following the initiation of a pipeline. This was a major factor that contributed to the determination of the low quality of evidence of these studies. Additionally, eighteen of the nineteen healthcare education programs included in this review reported post-pipeline outcomes at just a single time point. These things together make it difficult to determine whether significant improvements to representation are made as a result of pipeline intervention and whether improvements would be consistent or sustainable over multiple years.

While all studies reported on the types of services that were included in their pipeline initiative (such as mentorship, academic assistance, financial support, etc.), none commented on the consistency with which the services were applied across participants. There is a lack of clarity regarding whether all students in a pipeline received the same services, or whether they were instead provided access to the variety of services which they could then choose to utilize or not. This makes it difficult to determine the true impact of the pipeline, and any specific component in particular, in the presence of other potentially confounding factors.

Finally, all studies are at least 10 years old, and thus, the current trends in program- or institution-specific pipelines are unclear.


The institution of a pipeline may increase representation of racial and ethnic minority students within medical or dental education programs. Based on the present review, conclusions about the impact of a pipeline on other allied health profession education programs cannot be drawn.

Future research must include an evaluation of pipelines for graduate-level allied health professions such as physical and occupational therapy, speech language pathology, pharmacy, physician’s assistant, optometry, and chiropractic. It may also be beneficial to further explore the cost benefit of single healthcare program pipelines (such as those evaluated in this review) versus a more collective pipeline program that could serve a broader base of students and institutions, as well as perhaps have the resources to ensure sustainability over time. Finally, this review looked specifically at enrollment as an outcome. A closer evaluation of retention, both within a healthcare education program and within the chosen occupation, is also necessary if the ultimate goal is to improve diversity and representation among the healthcare workforce.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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