The Power of Statistical Tests for Moderators in Meta-Analysis.

Hedges, Larry V.; Pigott, Therese D.

doi:10.1037/1082-989x.9.4.426

Cited by 567 publications

(469 citation statements)

References 18 publications

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“…This did not appear to be simply function of limited statistical power because, based on the procedures described by Hedges and Pigott (2004) for mixed-effects regression models, we had a power of .54 to detect a small effect (r = .10), a power of .89 to detect a medium effect (r = .30), and a power of greater than .99 to detect a large effect (r = .50). These calculations were based on 2-tailed inferential tests and an assumed variance of .1, which was a conservative value that exceeded all observed error variances.…”

Section: Moderators Of Obesity Prevention Effectsmentioning

confidence: 99%

A meta-analytic review of obesity prevention programs for children and adolescents: The skinny on interventions that work.

Stice¹,

Shaw²,

Marti³

2006

Psychological Bulletin

574

571

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This meta-analytic review summarizes obesity prevention programs and their effects and investigates participant, intervention, delivery, and design features associated with larger effects. A literature search identified 64 prevention programs seeking to produce weight gain prevention effects, of which 21% produced significant prevention effects that were typically pre to post effects. Larger effects emerged for programs targeting children and adolescents (versus preadolescents) and females, programs that were relatively brief, programs solely targeting weight control versus other health behaviors (e.g., smoking), programs evaluated in pilot trials, and programs wherein participants must self-select into the intervention. Other factors, including mandated improvements in diet and exercise, sedentary behavior reduction, delivery by trained interventionists, and parental involvement, were not associated with significantly larger effects. A Meta-Analytic Review of Obesity Prevention Programs for Children and Adolescents: The Skinny on Interventions that WorkObesity in adulthood results in an increased risk for future death from all causes, coronary heart disease, atherosclerotic cerebrovascular disease, and colorectal cancer, as well as serious medical problems, including hyperlipidemia, hypertension, gallbladder disease, and diabetes mellitus (Calle, Thun, Petrelli, Rodriguez, & Heath, 1999). Obesity in childhood and adolescence is also associated with serious medical problems, including high blood pressure, adverse lipoprotein profiles, diabetes mellitus, atherosclerotic cerebrovascular disease, coronary heart disease, colorectal cancer, and death from all causes, as well as lower educational attainment and poverty (Dietz, 1998). The prevalence of obesity has increased sharply over the last three decades; currently 65% of adults are classified as overweight or obese (Hedley et al., 2004). The prevalence of obesity has risen even more sharply among adolescents and young adults (Hedley et al., 2004), which is alarming because obesity persists into adulthood for 70% of obese adolescents (Magarey, Daniels, Boulton, & Cockington, 2003). Obesity also carries a high fiscal cost; roughly $100 billion per year is spent on obesityrelated health care (Wolf, 1998).Unfortunately, successful treatments for obesity have been elusive. For adults, the current treatment of choice only results in about a 10% reduction in body weight and virtually all patients regain this weight within a few years of treatment . Obesity treatments for children and adolescents have yielded similar effects, though behavioral familybased interventions have produced more persistent weight loss effects (Epstein, Valoski, Wing, Correspondence should be addressed to Eric Stice, who is currently at Oregon Research Institute, 1715 Franklin Blvd., Eugene, Oregon, 97403. Email: estice@ori.org. Eric Stice, Heather Shaw, Department of Psychology, University of Texas at Austin. C. Nathan Marti, Department of Educational Administration, University of Tex...

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Section: Moderators Of Obesity Prevention Effectsmentioning

confidence: 99%

A meta-analytic review of obesity prevention programs for children and adolescents: The skinny on interventions that work.

Stice¹,

Shaw²,

Marti³

2006

Psychological Bulletin

574

571

View full text Add to dashboard Cite

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“…Fourth, the quality of included studies was variable (e.g., medication was allowed alongside psychotherapy in 23 studies). Although the results of subanalyses to examine the moderating effect of use of treatment manual, treatment fidelity, and medication use showed that these variables (pharmacotherapy use, treatment length, mean number of sessions, year of publication) did not account for a significant proportion of variance in treatment effects, power for testing moderators is often low (Borenstien et al, 2009;Hedges & Pigott, 2004). Additional points for consideration on methodological study quality such as blinding of observer-rated outcomes, reporting of intention to treat analyses, and the reliability of random allocation procedure may, however, have had an influence on treatment effects.…”

Section: Critical Analysismentioning

confidence: 99%

A meta-analysis of psychodynamic psychotherapy outcomes: Evaluating the effects of research-specific procedures.

et al. 2012

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The aim of this research was to examine the extent to which the use of research-specific procedures in psychodynamic psychotherapy impacts upon treatment effectiveness and which variables moderate this potential relationship. Effects of audio/video recording of sessions, use of treatment manuals, and checks of treatment fidelity were examined. A meta-analysis was conducted on randomized controlled trials of psychodynamic psychotherapy. Forty-six independent treatment samples totaling 1615 patients were included. The magnitude of change between pretreatment and posttreatment aggregated across all studies (45 treatment samples) for overall outcome was large (d ϭ 1.01), and further improvement was observed between posttreatment and an average 12.8-month follow-up (d ϭ 0.18). Subgroup analyses comparing studies that used research-specific procedures and those that did not revealed that for posttreatment data no differences in treatment effects were found. However, the use of treatment manuals and fidelity checks were significantly associated with improvement between the end of treatment and follow-up assessment. Within the limitations of analyses, this data offered preliminary evidence that use of research-specific procedures does not contribute in a negative manner to posttreatment outcomes in psychodynamic psychotherapy, and their use contributes to positive differences that emerge with time. These findings, although observational in nature, make a case for reconsidering how dimensions of clinical utility and experimental control may be integrated in psychodynamic psychotherapy to enable further elucidation of principles that evidently work.

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“…32 In addition, moderator analyses have only limited power with a small set of studies. 40,41 This latter limitation is particularly noteworthy given the substantial heterogeneity that was found in the elderly studies. Our results revealed that 68 percent of the variance in effect sizes across the elderly studies was attributable to systematic differences.…”

Section: Effectiveness Of Active Videogamesmentioning

confidence: 96%

“…38,39 Significant prediction indicates that the effect sizes vary in a linear manner with the continuous moderator. It should be noted, however, that the statistical power of moderator analyses in meta-analysis is not always high 40 and that a large number of studies is generally needed to detect effects. 41 Given that research about active videogames is still in its infancy, so that not many published studies exist, 9,16 the results of these analyses should be considered with caution.…”

Section: Effectiveness Of Active Videogamesmentioning

confidence: 99%

How Effective Are Active Videogames Among the Young and the Old? Adding Meta-analyses to Two Recent Systematic Reviews

RietJonathan

CrutzenRik

2014

Games for Health Journal

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Objective: Two recent systematic reviews have surveyed the existing evidence for the effectiveness of active videogames in children/adolescents and in elderly people. In the present study, effect sizes were added to these systematic reviews, and meta-analyses were performed. Materials and Methods: All reviewed studies were considered for inclusion in the meta-analyses, but only studies were included that investigated the effectiveness of active videogames, used an experimental design, and used actual health outcomes as the outcome measures (body mass index for children/adolescents [k = 5] and functional balance for the elderly [k = 6]). Results: The average effect of active videogames in children and adolescents was small and nonsignificant: Hedges' g = 0.20 (95 percent confidence interval, -0.08 to 0.48). Limited heterogeneity was observed, and no moderator analyses were performed. For the effect of active videogames on functional balance in the elderly, the analyses revealed a medium-sized and significant effect of g = 0.68 (95 percent confidence interval, 0.13-1.24). For the elderly studies, substantial heterogeneity was observed. Moderator analyses showed that there were no significant effects of using a no-treatment control group versus an alternative treatment control group or of using games that were especially created for health-promotion purposes versus off-the-shelf games. Also, intervention duration and frequency, sample size, study quality, and dropout did not significantly moderate the effect of active videogames. Conclusions: The results of these meta-analyses provide preliminary evidence that active videogames can have positive effects on relevant outcome measures in children/adolescents and elderly individuals.

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The Power of Statistical Tests for Moderators in Meta-Analysis.

Cited by 567 publications

References 18 publications

A meta-analytic review of obesity prevention programs for children and adolescents: The skinny on interventions that work.

A meta-analytic review of obesity prevention programs for children and adolescents: The skinny on interventions that work.

A meta-analysis of psychodynamic psychotherapy outcomes: Evaluating the effects of research-specific procedures.

How Effective Are Active Videogames Among the Young and the Old? Adding Meta-analyses to Two Recent Systematic Reviews

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