# effect size

## lmeInfo

Information Matrices for 'lmeStruct' and 'glsStruct' Objects

## Simulating correlated standardized mean differences for meta-analysis

As I’ve discussed in previous posts, meta-analyses in psychology, education, and other areas often include studies that contribute multiple, statistically dependent effect size estimates. I’m interested in methods for meta-analyzing and meta-regressing effect sizes from data structures like this, and studying this sort of thing often entails conducting Monte Carlo simulations.

## Sometimes, aggregating effect sizes is fine

In meta-analyses of psychology, education, and other social science research, it is very common that some of the included studies report more than one relevant effect size. For example, in a meta-analysis of intervention effects on reading outcomes, some studies may have used multiple measures of reading outcomes (each of which meets inclusion criteria), or may have measured outcomes at multiple follow-up times; some studies might have also investigated more than one version of an intervention, and it might be of interest to include effect sizes comparing each version to the no-intervention control condition; and it’s even possible that some studies may have all of these features, potentially contributing lots of effect size estimates.

## Procedural sensitivities of effect sizes for single-case designs with behavioral outcome measures

A wide variety of effect size indices have been proposed for quantifying the magnitude of treatment effects in single-case designs. Commonly used measures include parametric indices such as the standardized mean difference, as well as non-overlap …

## Between-case standardized effect size analysis of single case design: Examination of the two methods

An increasing movement in single case research is to employ statistical analyses as one form of data analysis. Researchers have proposed different statistical approaches. The purpose of this paper is to examine the utility and discriminant validity …

## New paper: A gradual effects model for single-case designs

I’m very happy to share a new paper, co-authored with my student Danny Swan, “A gradual effects model for single-case designs,” which is now available online at Multivariate Behavioral Research.

## A gradual effects model for single-case designs

Single-case designs are a class of repeated measures experiments used to evaluate the effects of interventions for specialized populations, such as individuals with low-incidence disabilities. There has been growing interest in systematic reviews and …

## Sampling variance of Pearson r in a two-level design

Consider Pearson’s correlation coefficient, $$r$$, calculated from two variables $$X$$ and $$Y$$ with population correlation $$\rho$$. If one calculates $$r$$ from a simple random sample of $$N$$ observations, then its sampling variance will be approximately

## New paper: Using response ratios for meta-analyzing SCDs with behavioral outcomes

I’m pleased to announce that my article “Using response ratios for meta-analyzing SCDs with behavioral outcomes” has been accepted at Journal of School Psychology. There’s a multitude of ways that you can access this work:

## Using response ratios for meta-analyzing single-case designs with behavioral outcomes

Methods for meta-analyzing single-case designs (SCDs) are needed to inform evidence-based practice in clinical and school settings and to draw broader and more defensible generalizations in areas where SCDs comprise a large part of the research base. …