This article reviews the origins and use of the terms quasi-experiment and natural experiment. It demonstrates how the terms conflate whether variation in the independent variable of interest falls short of random with whether researchers find, rather than intervene to create, that variation. Using the lens of assignment--the process driving…

Psychologists are emphasizing the importance of predictive conclusions. Machine learning methods, such as supervised neural networks, have been used in psychological studies as they naturally fit prediction tasks. However, we are concerned about whether neural networks fitted with random datasets (i.e., datasets where there is no relationship…

A linear model is often used to find the effect of a binary treatment D on a noncontinuous outcome Y with covariates X. Particularly, a binary Y gives the popular "linear probability model (LPM)," but the linear model is untenable if X contains a continuous regressor. This raises the question: what kind of treatment effect does the…

Understanding the factors associated with variation in the implementation of educational programs has emerged as a key research focus, in an effort to identify how promising programs can be scaled up across their targeted contexts. The current study explored demographic-related variation in program dosage using a novel source of implementation…

Multi-site randomized controlled trials (RCTs) provide unbiased estimates of the average impact in the study sample. However, their ability to accurately predict the impact for individual sites outside the study sample, to inform local policy decisions, is largely unknown. To extend prior research on this question, we analyzed six multi-site RCTs…

Longitudinal survey and experimental research is essential for understanding psychological and economic processes, but attrition is a concern. We examine attrition in a 2016 longitudinal randomized controlled trial of more than 13,000 prospective U.S. homeowners, in which participants were invited to up to seven online surveys delivered every two…

The current study examined predictors of outcomes across two school clinician-delivered treatments (i.e., treatment as usual [TAU] or modular cognitive-behavioral therapy [M-CBT]) for youth with anxiety disorders. Predictors reflected two broad domains -- therapist factors (i.e., education, years of experience, therapeutic orientation, work…

Background/Context: Early childhood education research has consistently found evidence of immediate, positive effects on developmental outcomes. Despite these strong initial benefits, follow-up analyses often reveal that these effects fadeout in the years following participation (e.g., Bailey et al., 2017, Clements et al., 2013; Lipsey et al.…

Recent methods have sought to improve precision in randomized controlled trials (RCTs) by utilizing data from large observational datasets for covariate adjustment. For example, consider an RCT aimed at evaluating a new algebra curriculum, in which a few dozen schools are randomly assigned to treatment (new curriculum) or control (standard…

Background: It has become increasingly important to shift education research and programming from a deficit focused perspective to a positive youth development perspective in order to identify and promote factors that support students' positive functioning and outcomes. One outgrowth of positive youth development is Positive Mental Health (PMH),…