A mediation effect explains the relationship of a risk factor and an outcome through a mediator variable which is a step in their pathway. Under the assumption of no cycling in the causal relationship, we consider various situations in which a fourth variable may interfere the estimation of a mediation effect as a confounding factor. Our asymptotic results, which are supported by a Monte Carlo ...

BACKGROUND Mediation is an important issue considered in the behavioral, medical, and social sciences. It addresses situations where the effect of a predictor variable X on an outcome variable Y is explained to some extent by an intervening, mediator variable M. Methods for addressing mediation have been available for some time. While these methods continue to undergo refinement, the relationsh...

As more and more divorcing couples use mediation rather than the traditional litigation process to resolve their divorce issues, the effectiveness of mediation has captured the attention of researchers. However, the results vary across divorce mediation and litigation outcome studies. Because a quantitative review has never been performed and the overall efficacy of mediation as an alternative ...

Mediation analysis has become one of the most popular statistical methods in the social sciences. However, many currently available effect size measures for mediation have limitations that restrict their use to specific mediation models. In this article, we develop a measure of effect size that addresses these limitations. We show how modification of a currently existing effect size measure res...

Mediation models are widely used, and there are many tests of the mediated effect. One of the most common questions that researchers have when planning mediation studies is, "How many subjects do I need to achieve adequate power when testing for mediation?" This article presents the necessary sample sizes for six of the most common and the most recommended tests of mediation for various combina...

Results vary across divorce mediation and litigation outcome studies. Because a quantitative review has never been performed on this body of research, the present study conducts a meta-analysis on this literature. From five studies that met the established inclusion criteria, it was found that mediation produced a grand effect size of 0.36. This smallto-moderate effect size reveals that across ...

We revisited the three interrelated epidemiological concepts of effect modification, interaction and mediation for clinical investigators and examined their applicability when using research databases. The standard methods that are available to assess interaction, effect modification and mediation are explained and exemplified. For each concept, we first give a simple "best-case" example from a...

Mediation models figure out how an effect occurred by hypothesizing a causal sequence. For a simple mediation model, a causal sequence is described in which an independent variable causes the mediator which sequentially causes the dependent variable. In this article, we tried to introduce to use standardized regression coefficient to the involving the simple mediation model since a standardized...