Critiques "The Statistical Analysis of Quasi-Experiments" by Achen and examines its relevance for historians. Discusses the problems that arise when quasi-experiments involving nonrandom assignment or nonrandom selection are analyzed as if they were true experiments. Concludes that Achen's book will help historians recognize these…

Asserts that traditional approaches to multivariate analysis, including standard linear regression techniques, ignore the special character of count data. Explicates three suitable alternatives to standard regression techniques, a simple Poisson regression, a modified Poisson regression, and a negative binomial model. (MJP)