The ultimate goal of HIV prevention interventions is to reduce the spread of HIV; however, the effectiveness of these programs is seldom assessed directly. Although direct measurement of an intervention's impact via HIV seroincidence monitoring is usually unfeasible, mathematical models can be...

In developed countries, researchers who study competence in children have reported weak to moderate correlations among the three most commonly considered domains: academic per formance, peer relations, and conduct. Associations among these domains have not been studied in children who live in...

When modeling multilevel data, it is important to accurately represent the interdependence of observations within clusters. Ignoring data clustering may result in parameter misestimation. However, it is not well established to what degree parameter estimates are affected by model...

In this paper we describe MIDAS: a SAS macro for multiple imputation using distance aided selection of donors which implements an iterative predictive mean matching hot-deck for imputing missing data. This is a flexible multiple imputation approach that can handle data in a variety of formats:...

The coefficient of determination, known also as the R2, is a common measure in regression analysis. Many scientists use the R2 and the adjusted R2 on a regular basis. In most cases, the researchers treat the coefficient of determination as an index of 'usefulness' or 'goodness of fit,' and in...

Comparing regression coefficients between models when one model is nested within another is of great practical interest when two explanations of a given phenomenon are specified as linear models. The statistical problem is whether the coefficients associated with a given set of covariates change...

When an assumption of missing at random is untenable, it becomes necessary to model missing-data indicators, which carry information about the parameters of the complete-data population. Within a given application, however, researchers may believe that some aspects of missingness are ignorable...

Purpose – The aim of this paper is to evaluate the effectiveness of The Leadership Program's Violence Prevention Project (VPP) – a 12‐session programme consisting of explicit curriculum‐based classroom instruction designed for adolescents to promote a range of communication skills...