The product Bayes factor (PBF) synthesizes evidence for an informative hypothesis across heterogeneous replication studies. It can be used when fixed- or random effects meta-analysis fall short. For example, when effect sizes are incomparable and cannot be pooled, or when studies diverge significantly in the populations, study designs, and…

Educators who are urged to use evidence-based practices to improve instruction often end up disappointed at the results, which fall short of those touted in the research and by the What Works Clearinghouse. Stanley Pogrow explains how common strategies researchers use to demonstrate evidence of success, such as statistical significance of or…

Effect sizes are important because they are an accessible way to indicate the practical importance of observed associations or differences. Standardized mean difference (SMD) effect sizes, such as Cohen's d, are widely used in education and the social sciences -- in part because they are relatively easy to calculate. However, SMD effect sizes…

Empirical growth benchmarks, as introduced by Hill, Bloom, Black, and Lipsey (2008), are a well-known way to contextualize effect sizes in education research. Past work on these benchmarks, both positive and negative, has largely avoided confronting the role of vertical scales, yet technical issues with vertical scales trouble the use of such…

This supplement concerns Appendix E of the "What Works Clearinghouse (WWC) Procedures Handbook, Version 4.1." The supplement extends the range of designs and analyses that can generate effect size and standard error estimates for the WWC. This supplement presents several new standard error formulas for cluster-level assignment studies,…

Children develop and learn within dynamic contexts, yet the simplifying assumptions of common statistical methods often relegate such complexity to unexplained error. This chapter discusses ideas from the dynamic systems literature, which focuses on the interplay within and between components of complex systems, such as individuals and their…

Active learning research emerged from the undergraduate STEM education communities of practice, some of whom identify as discipline-based education researchers (DBER). Consequently, current frameworks of active learning are largely inductive and based on emergent patterns observed in undergraduate teaching and learning. Alternatively, classic…

Effect sizes are powerful tools for evaluating the practical importance of study findings that should be considered in the context of study characteristics such as participants, dependent variables, and comparison condition. In this article, we discuss how group-difference effect sizes are used to gauge the practical importance of group…

This document summarises key findings from the quantitative strands of a review of the Education Endowment Foundation (EEF) evaluations that had reported from the establishment of EEF in 2011 up to January 2019. The quantitative strands summarised include meta-analyses of effect sizes reported for attainment outcomes and descriptive analyses of…

A simple synthesis of fluorescent carbon quantum dots from lemon juice is described to introduce advanced high-school students and undergraduate college students to nanoparticle synthesis and quantum dots. The synthesis is based on the carbonization of lemon juice using only a hot plate stirrer. Column chromatography is used to separate different…

Much of the evidential basis for recent policy decisions is grounded in effect size: the standardised mean difference in outcome scores between a study's intervention and comparison groups. This is interpreted as measuring educational influence, importance or effectiveness of the intervention. This article shows this is a category error at two…

Large-scale randomized studies provide the best means of evaluating practical, replicable approaches to improving educational outcomes. This article discusses the advantages, problems, and pitfalls of these evaluations, focusing on alternative methods of randomization, recruitment, ensuring high-quality implementation, dealing with attrition, and…

In many situations, the change in the conceptual understanding of students is measured using a single question. This is, for instance, the case in peer instruction where students answer twice to the same questions, before and after the discussion phase. Using item response theory and assuming that students proficiencies are normally distributed,…

The purpose of this article is to present various single-case outcome assessment methods for evaluating school-based intervention effectiveness. We present several outcome methods, including goal attainment scaling, visual analysis, trend analysis, percentage of non-overlapping data, single-case mean difference effect size, reliable change index,…

This Study Snapshot highlights key findings from a study that examines up-to-date information about evidence-based practices that are essential for early childhood educators and policymakers as they support preschool children's language and literacy development. The study used a process modeled after the What Works Clearinghouse (WWC) methodology…