Why Cohen’s effect size rule should be avoided

From Durlak (2009), How to select, calculate, and interpret effect sizes: Many authors still routinely refer to Cohen’s (1988) comments made in reference to power analysis that SMDs of 0.20 are “small” in magnitude, those around 0.50 are “medium” and those around or above 0.80 are “large.” In terms of r, Cohen suggested corresponding figures of 0.10, 0.30, and 0.50. What many researchers do...

Have we reached peak NSSE?

More trend data from their annual reports: There is a clear decline in the past five years. While some of this is probably due to institutions using the NSSE on a less than annual basis, I think there is a real decline here (the fact that schools may be using it less frequently is also an indicator of how useful they are finding it). My prediction is that this decline will continue as...

College student survey response rates continue to decline

Depressingly, average institutional response rates for the NSSE have dropped over 10 percentage points during the last decade, to 30% in their most recent annual report. While the content of the NSSE leaves much to be desired, their response rates are a good indicator of what is happening across the country on college campuses. Some of this decline is probably due to survey fatigue; some may be...

Matching and complex survey data

Several people have asked me about using propensity score matching with complex surveys, and whether/how weights, PSUs and strata should be taken into account. This paper explains how to handle these issues.

Measuring college student learning in the UNC system

The General Education Council of the UNC General Administration asked me to give a presentation on issues around measuring student learning in higher education. Slides are here.
The state has adopted an ambitious strategic plan; one of their stated strategies is “Become a national leader in the assessment of student learning gains” (p. 44).

About me


Professor and quant guy. Libertarian turned populist Republican. Trying to learn Japanese and play Spanish Baroque music on the ukulele.

Subscribe via email

Enter your email address to subscribe to my blog and receive notifications of new posts by email.