design-comparable SMD

Between-case standardized mean differences: Flexible methods for single-case designs

Single-case designs (SCDs) are a class of research methods for evaluating the effects of academic and behavioral interventions in educational and clinical settings. Although visual analysis is typically the first and main method for primary analysis …

Cohen's $d_z$ makes me dizzy when considering measurement error

Meta-analyses in education, psychology, and related fields rely heavily of Cohen's $d$, or the standardized mean difference effect size, for quantitatively describing the magnitude and direction of intervention effects. In these fields, Cohen's $d$ is so pervasive that its use is nearly automatic, and analysts rarely question its utility or consider alternatives (response ratios, anyone? POMP?). Despite this state of affairs, working with Cohen's $d$ is theoretically challenging because the standardized mean difference metric does not have a singular definition. Rather, its definition depends on the choice of the standardizing variance used in the denominator.

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 …

A meta-analysis of school-based group contingency interventions for students with challenging behavior: An update

Group contingencies are recognized as a potent intervention for addressing challenging student behavior in the classroom, with research reviews supporting the use of this intervention platform going back more than four decades. Over this time period, …

A meta-analysis of technology-aided instruction and intervention for students with ASD

The adoption of methods and strategies validated through rigorous, experimentally oriented research is a core professional value of special education. We conducted a systematic review and meta-analysis examining the experimental literature on …

Functional assessment-based interventions for students with or at-risk for high incidence disabilities: Field-testing single-case synthesis methods

This systematic review investigated one systematic approach to designing, implementing, and evaluating functional assessment–based interventions (FABI) for use in supporting school-age students with or at-risk for high-incidence disabilities. We …

Research synthesis and meta-analysis of single-case designs

Between-case standardized mean difference effect sizes for single-case designs: A primer and tutorial using the scdhlm web application

We describe a standardised mean difference statistic (d) for single-case designs that is equivalent to the usual d in between-groups experiments. We show how it can be used to summarise treatment effects over cases within a study, to do power …

New tutorial paper on BC-SMD effect sizes

I’m pleased to announce that the Campbell Collaboration has just published a new discussion paper that I wrote with my colleagues Jeff Valentine and Emily Tanner-Smith about between-case standardized mean difference effect sizes for single-case designs.

scdhlm

Between-case SMD for single-case designs