Studies that examine the effects of neighborhood characteristics on mental health show that perceptions of general neighborhood violence are associated with depression across diverse populations (Clark et al., 2008; Velez-Gomez et al., 2013; Wilson-Genderson & Pruchno, 2013). However, to our...

The conventional approach of choosing sample size to provide 80% or greater power ignores the cost implications of different sample size choices. Costs, however, are often impossible for investigators and funders to ignore in actual practice. Here, we propose and justify a new approach for...

In standard regression analyses of clustered data, one typically assumes that the expected value of the response is independent of cluster size. However, this is often false. For example, in studies of surgical interventions, investigators have frequently found surgery volume and outcomes to be...

We consider the situation where the random effects in a generalized linear mixed model may be correlated with one of the predictors, which leads to inconsistent estimators. We show that conditional maximum likelihood can eliminate this bias. Conditional likelihood leads naturally to the...