This meta-analysis examined the ecological and population validity of intervention research for students with low mathematics achievement (SWLMA). Forty-four studies published between 2005 and 2019 that met the inclusionary criterion were included in this analysis. Our findings suggest, to improve the external validity and generalizability of…

Group design research studies can provide evidence to draw conclusions about "what works," "for whom," and "under what conditions" in special education. The quality indicators introduced by Gersten and colleagues (2005) have contributed to increased rigor in group design research, which has provided substantial…

The problem of assessing whether experimental results can be replicated is becoming increasingly important in many areas of science. It is often assumed that assessing replication is straightforward: All one needs to do is repeat the study and see whether the results of the original and replication studies agree. This article shows that the…

The problem of assessing whether experimental results can be replicated is becoming increasingly important in many areas of science. It is often assumed that assessing replication is straightforward: All one needs to do is repeat the study and see whether the results of the original and replication studies agree. This article shows that the…

The purposes of this manuscript are to identify common statistical mistakes in sport management, and to provide scholars with suggestions on how to develop and improve the quality of quantitative research. We have reviewed articles published from 2001 to 2017 in the "Journal of Sport Management," "Sport Management Review,"…

More aggregate data on school performance is available than ever before, opening up new possibilities for applied researchers interested in assessing the effectiveness of school-level interventions quickly and at a relatively low cost by implementing comparative interrupted times series (CITS) designs. We examine the extent to which effect…

Researchers often include covariates when they analyze the results of randomized controlled trials (RCTs), valuing the increased precision of the estimates over the potential of inducing small-sample bias when doing so. In this paper, we develop a sufficient condition which ensures that the inclusion of covariates does not induce small-sample bias…

Momentary time sampling (MTS), whole interval recording (WIR), and partial interval recording (PIR) are commonly used in applied research. We discuss potential difficulties with analyzing data when these systems are used and present results from a pilot simulation study designed to determine the extent to which these issues are likely to be…

Proactive preliminary minimum sample size determination can be useful for the early planning stages of a latent variable modeling study to set a realistic scope, long before the model and population are finalized. This study examined existing methods and proposed a new method for proactive preliminary minimum sample size determination.

Randomized experiments provide unbiased estimates of treatment effects, but are costly and time consuming. We demonstrate how a randomized experiment can be leveraged to measure selection bias by conducting a subsequent observational study that is identical in every way except that subjects choose their treatment--a quasi-doubly randomized…

The authors examined 2 approaches for determining the required sample size of Welch's test for detecting equality of means when the greatest difference between any 2 group means is given. It is shown that the actual power obtained with the sample size of the suggested approach is consistently at least as great as the nominal power. However, the…

The purpose of this study was to examine the quality of quantitative articles published in the "Journal of Counseling & Development." Quality concerns arose in regard to omissions of psychometric information of instruments, effect sizes, and statistical power. Type VI and II errors were found. Strengths included stated research…

There is currently a considerable diversity of quantitative measures available for summarizing the results in single-case studies. Given that the interpretation of some of them is difficult due to the lack of established benchmarks, the current article proposes an approach for obtaining further numerical evidence on the importance of the results,…

The purpose of this systematic review was to investigate the weight of scientific evidence regarding student outcomes (physical, cognitive and affective) of a Game Centered Approach (GCA) when the quality of a study was taken into account in the interpretation of collective findings. A systematic search of five electronic databases (Sports…

This review assessed the use of self-regulated strategy development (SRSD) for teaching written composition strategies to students with attention deficit hyperactivity disorders. We examined the participants and the settings in which SRSD has been used, the writing strategies tested, genres addressed, and the effects of SRSD on outcome measures.…