Understanding Variation in Estimates of Diversionary Effects of Community College Entrance: A Systematic Review and Meta-analysis.

Decades of research have estimated the effect of entering a community college on bachelor's degree attainment. In this study, we examined the influence of methodological choices, including sample restrictions and identification strategies, on estimated effects from studies published between 1970 and 2017. After systematically reviewing the literature, we leveraged meta-analysis to assess average estimates and examine the role of moderators. In our preferred model, entering a community college was associated with a 23-percentage-point decrease in the probability of baccalaureate attainment, on average, compared with entering a four-year college. The size of effects appeared to grow over the past three decades, though this coincides with substantial shifts in the college-going population. Methodological choices, particularly how researchers define the treatment group, explain some variation in estimates across studies. We conclude with a discussion of the implications for future inquiry and for policy.