New Empirical Study of Rule 23(f) Class-Certification Appeals


I completed a study of Rule 23(f) petitions filed from 2013 through 2017, finding little support for common criticisms of the rule.


I’ve been studying interlocutory class-certification appeals for a while now, and my draft article on the topic—Interlocutory Class-Certification Appeals Under Rule 23(f)—is now up on SSRN. I created a dataset of petitions to appeal class-certification decisions under Federal Rule of Civil Procedure 23(f) filed from 2013 through 2017. The draft presents my findings, such as the number of petitions filed, the rate at which they’re granted (nationally and by circuit), and—when courts grant petitions to appeal—decisions on the merits of class certification.

I also analyzed whether the data support (or supports, depending on how you feel about whether data is singular or plural) two common criticisms of Rule 23(f). Rule 23(f) has few fans. Some critics contend that the rule operates largely to defendants’ benefit. Others contend that the courts apply the rule inconsistently. I found little support for either criticism in the data. And what little support there is comes with some serious caveats and needs further research.

The abstract is below. I welcome comments all comments and suggestions.

This Article presents my empirical study of petitions to appeal from class-certification decisions under Federal Rule of Civil Procedure 23(f). I created a dataset of Rule 23(f) petitions filed from 2013 through 2017. The data revealed three insights on Rule 23(f) and class actions generally.

First are the basic findings. Litigants filed over 850 petitions to appeal from 2013 through 2017. The courts of appeals granted about 25% of them. And when appellate courts granted permission to appeal, they reversed the district court’s class-certification decision about 54% of the time.

Second, I used the data to test two common criticisms of Rule 23(f): (1) that the rule favors defendants, and (2) that the circuits apply the rule inconsistently. I found little empirical support for either of these criticisms. And what little evidence there is comes with some significant caveats.

Finally, the data shed some light on the largely unknown universe of class actions. We have very little hard data on class actions—how many are brought, the types of cases, their success rate, etc. And some question whether the class action is still a viable tool for plaintiffs to obtain relief. My study provides a glimpse into one corner of the class-action universe. And, perhaps surprisingly, it’s a corner in which plaintiffs are not always losing: in the Rule 23(f) context, the courts of appeals reached a plaintiff-favorable outcome over 50% of the time.

You can download the draft on SSRN.