Counterfactuals, causal effect heterogeneity, and the catholic school effect on learning

School-effects research in sociology cannot be separated from concerns abou t causality. Purely descriptive modeling justifications are untenable. Focu sing on the Catholic school effect on learning, this article demonstrates a n approach that places regression modeling strategies within a specific and well-developed framework for thinking about causality. While regression mo dels should properly remain the workhorse methodology for school-effects re search, regression estimates should more often be subject to exacting inter pretations and presented alongside alternative estimates of more specific p arameters of interest. In this demonstration, propensity-score matching est imates of the Catholic school effect for the Catholic schooled are provided to supplement the estimates obtained by regression models. Although subjec t to their own set of weaknesses, the matching estimates suggest that the C atholic school effect is the strongest among those Catholic school students who, according to their observed characteristics, are least likely to atte nd Catholic schools. Four alternative explanations are offered for this fin ding, each of which should be pursued in further research.