Background and Purpose–Factor V Leiden and a prothrombin gene variant, G20210A, are mutations associated with a thrombotic risk. The aim of our study was to assess whether these mutations increase the risk of stroke in women under 45 years of age. Methods–We conducted a case-control study in western Washington state. Case patients were women aged… Continue reading Risk of Stroke in Young Women and Two Prothrombotic Mutations: Factor V Leiden and Prothrombin Gene Variant (G20210A)

Nonresponse weighting is a common method for handling unit nonresponse in surveys and is aimed at reducing nonresponse bias. Because the method can be accompanied by an increase in variance, the efficacy of weighting adjustments is often seen as a bias-variance trade-off. This view is an oversimplification, because weighting can reduce variance as well as… Continue reading Does weighting for nonresponse increase the variance of survey means?

A central problem in public health studies is how to make inferences about the causal effects of treatments or agents. In this article we review an approach to making such inferences via potential outcomes. In this approach, the causal effect is defined as a comparison of results from two or more alternative treatments, with only… Continue reading Causal effects in clinical and epidemiological studies via potential outcomes: Concepts and Analytical Approaches

A formal comparison is made between direct standardization and three cross- classified data structures: tables of means which are linear additive; tables of means which are log-linear additive; and tables of frequencies which are log-linear addi tive and can be converted to tables of proportions which are logit-linear additive. Standardization is an appropriate method of… Continue reading The General Linear Model and Direct Standardization: A Comparison