In Italian state universities candidate freshmen must take an entrance examination. Candidates who obtain a test score less than or equal to a pre‐fixed threshold may enrol at the university but must comply with an additional compulsory educational obligation, called obblighi formativi aggiuntivi (OFA). The OFA assignment rule appeals to a (sharp) regression discontinuity design with the entrance examination score acting as the forcing variable. We assess causal effects of OFA status by using data from a school of engineering of a specific Italian state university. For subpopulations of units for which our regression discontinuity design can be described as a local randomized experiment, we draw inference on the causal effects of OFA on students’ academic performances measured by using two variables: the number of university credits awarded at the end of the first academic year and the corresponding average grade. These outcome variables suffer from the problem of truncation by ‘death’, because neither is defined for students who decide not to enrol. Moreover, nor is the average grade defined for students who enrol but do not either take or pass any examination in the first academic year. We deal with these issues by using the framework of principal stratification and adopting a Bayesian approach to inference. We find some evidence that the receipt of OFA may negatively affect students’ academic performances, although the posterior distributions of the causal estimands have high variability.

中文翻译：

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评估额外义务学习对大学生学习成绩的因果关系

在意大利国立大学，应届新生必须参加入学考试。考试分数小于或等于预先确定的门槛的候选人可以入读大学，但必须遵守额外的义务教育义务，称为obblighi formativi aggiuntivi（OFA）。OFA分配规则吸引（锐化）回归不连续性设计，以入学考试成绩为强迫变量。我们使用来自意大利特定州立大学工程学院的数据评估OFA地位的因果关系。对于可以将我们的回归不连续性设计描述为局部随机实验的单元的子群体，我们使用两个变量来推断OFA对学生学习成绩的因果关系：两个变量：第一学年和相应的平均成绩。这些结果变量受“死亡”的截断问题困扰，因为对于决定不报名的学生都没有定义。此外，入学但未参加或未通过任何考试的学生的平均成绩也未定义。我们通过使用主体分层框架并采用贝叶斯推理方法来处理这些问题。我们发现一些证据表明，尽管因果估计的后验分布具有很高的可变性，但OFA的接收可能会对学生的学习成绩产生负面影响。