Effects of Explicit Vocabulary Interventions for Preschoolers: An Exploratory Application of the Percent of Goal Obtained Effect Size Metric

Sep 14, 2026

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Purpose: Systematic reviews are routinely used to identify effective educational and clinical practices, yet combining group experimental design (GED) and single-case experimental design (SCED) results remains challenging. This study extends Percent of Goal Obtained (PoGO) by estimating standard errors so PoGO can function as an effect size metric in meta-analyses across both design types. Sixteen studies on explicit vocabulary instruction for pre-K and kindergarten were analyzed, and PoGO with standard errors and confidence limits was computed for applicable treatment conditions. Results showed PoGO values ranging from 14.4% to 93.6%.

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CategoryResearch & Report

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Pages16

Reading Time40 min

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Abstract

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Background and Rationale

| Review Article
Effects of Explicit Vocabulary Interventions for Preschoolers: An Exploratory Application of the Percent of Goal Obtained Effect
Size Metric
Ella Patrona,a John Ferron,a Arnold Olszewski,b Elizabeth Kelley,c and Howard Goldsteina
a University of South Florida, Tampa b Miami University, Oxford, OH c University of Missouri, Columbia | | | --- | --- | | A R T I C L E I N F O
Article History:
Received April 16, 2022
Revision received July 4, 2022
Accepted August 31, 2022
Editor-in-Chief: Stephen M. Camarata
Editor: Megan York Roberts
[https://doi.org/10.1044/2022_JSLHR-22-00217](https://doi.org/10.1044/2022_JSLHR-22-00217) | A B S T R A C T | | | Purpose: Systematic reviews of literature are routinely conducted to identify practices that are effective in addressing educational and clinical problems. One complication, however, is how best to combine data from both group experimental design (GED) studies and single-case experimental design (SCED) studies. Percent of Goal Obtained (PoGO) has been developed as a metric to express the size of the effect relative to the distance to a goal, which could have broad applicability. This study sought to augment this descriptive index with estimates of standard errors, which are needed to use PoGO as an effect size metric in meta-analyses of SCED and GED studies. This study investigated the application of PoGO and standard errors to both SCED and GED studies examining a common intervention approach used with a single population. Method: Sixteen articles investigating explicit vocabulary instruction applied topre-K and kindergarten students were identified. PoGO and standard errors were calculated for variations of explicit vocabulary interventions. Evaluated interventions included six studies using exclusively an SCED, nine studies using a GED, and one that used both.
Results: PoGO was calculated for each treatment condition when applicable (i.e., alternating treatments designs) . Standard errors and confidence interval limits also were calculated. PoGO effect size values ranged from 14.4% to 93.6% . PoGO for single-case experiments was 49.2% with a standard error of 7.26, and for group experiments, it was 30.8% with a standard error of 3.71 . Conclusion: Despite variation in the percentage of goal obtained across studies, the high degree of overlap in PoGO and standard errors between singlecase and group experiments provides an indication that systematic reviews can apply this effect size metric to combine information obtained across experimental designs. | Educators, clinicians, and other practitioners are expected to provide efficacious and efficient services to their students and clients. Rather than relying on the findings of a single study to identify best practices, they increasingly rely on systematic reviews of the empirical studies that evaluate the effects of interventions that are designed to address educational and clinical problems of interest. Indeed, Correspondence to Howard Goldstein: [hgoldstein@usf.edu.](hgoldstein@usf.edu. Disclosure:)[ Disclosure:](hgoldstein@usf.edu. Disclosure:)[ ](hgoldstein@usf.edu. Disclosure:)The authors have declared that no competing financial or nonfinancial interests existed at the time of publication. systematic reviews have become increasingly more important as a source of information for clinicians to identify empirically supported interventions (Schlosser & Sigafoos, 2008, 2009) . One complication in identifying empirically supported interventions is the high likelihood that thereview will include both group experimental design (GED) studies and single-case experimental design (SCED) studies. For example, Sanders et al. (2019) conducted a metaanalysis of self-regulated strategy development reading interventions to improve the reading comprehension of students with disabilities that included four GED studies and five SCEDs. Similarly, Wood et al. (2018) meta-analyzed Journal of

FAQs

What problem does this study address in systematic reviews of interventions?

It addresses the difficulty of combining evidence from GED studies and SCED studies, especially when using effect size metrics that are hard to compare or interpret across designs.

How does the study extend PoGO for use in meta-analyses?

It augments the descriptive PoGO index by estimating standard errors, enabling PoGO to be used as an effect size metric in meta-analyses that include both SCED and GED studies.

What range of PoGO effect sizes was observed?

PoGO effect size values ranged from 14.4% to 93.6%, with reported standard errors and separate summaries for single-case and group experiments.

Sep 14, 2026

Uploaded by Fez