Law Commons^™

Power And Statistical Significance In Securities Fraud Litigation, Jill E. Fisch, Jonah B. Gelbach

All Faculty Scholarship

Event studies, a half-century-old approach to measuring the effect of events on stock prices, are now ubiquitous in securities fraud litigation. In determining whether the event study demonstrates a price effect, expert witnesses typically base their conclusion on whether the results are statistically significant at the 95% confidence level, a threshold that is drawn from the academic literature. As a positive matter, this represents a disconnect with legal standards of proof. As a normative matter, it may reduce enforcement of fraud claims because litigation event studies typically involve quite low statistical power even for large-scale frauds.

This paper, written for …

Constitutionalism And Democracy Dataset, Version 1.0, Todd A. Eisenstadt, Carl Levan, Tofigh Maboudi

Political Science: Faculty Publications and Other Works

The main objective of the CDD is to quantify the process of constitution-making since 1974. This is the first public release of any data on the process of constitution-making. This release includes data on 144 national constitutions promulgated in 119 countries from 1974 to 2014. The unit of analysis in the data is national constitutions. The data in this release includes only “new” constitutions and does not include suspended, re-installed, amended, or interim constitutions. In this release, only countries with a population larger than 500,000 are included. The authors intend to update the data by including all countries, expanding the …

When 10 Trials Are Better Than 1000: An Evidentiary Perspective On Trial Sampling, Edward K. Cheng

Vanderbilt Law School Faculty Publications

In many mass tort cases, separately trying all individual claims is impractical, and thus a number of trial courts and commentators have explored the use of statistical sampling as a way of efficiently processing claims. Most discussions on the topic, however, implicitly assume that sampling is a “second best” solution: individual trials are preferred for accuracy, and sampling only justified under extraordinary circumstances. This Essay explores whether this assumption is really true. While intuitively one might think that individual trials would be more accurate at estimating liability than extrapolating from a subset of cases, the Essay offers three ways in …

Will Quants Rule The (Legal) World?, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Professor Ian Ayres, in his new book, Super Crunchers, details the brave new world of statistical prediction and how it has already begun to affect our lives. For years, academic researchers have known about the considerable and at times surprising advantages of statistical models over the considered judgments of experienced clinicians and experts. Today, these models are emerging all over the landscape. Whether the field is wine, baseball, medicine, or consumer relations, they are vying against traditional experts for control over how we make decisions. For the legal system, the take-home of Ayres's book and the examples he describes is …