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.

中文翻译：

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理解社区大学入学分流效应估算的变化：系统评价和荟萃分析

数十年的研究估计，进入社区大学对学士学位的影响。在本研究中，我们研究了方法选择的影响（包括样本限制和识别策略）对1970年至2017年发表的研究的估计效果的影响。在系统回顾文献后，我们利用荟萃分析来评估平均估计值并研究版主。在我们的首选模型中，与进入四年制大学相比，进入社区大学与获得学士学位的概率平均降低了23个百分点。在过去的三十年中，影响的规模似乎有所增加，尽管这与大学人口的巨大变化相吻合。方法的选择，特别是研究人员如何定义治疗组，解释各研究估算值的差异。最后，我们讨论了对未来查询和政策的影响。