دورية أكاديمية
Designing Intervention Studies: Selected Populations, Range Restrictions, and Statistical Power
العنوان: | Designing Intervention Studies: Selected Populations, Range Restrictions, and Statistical Power |
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اللغة: | English |
المؤلفون: | Miciak, Jeremy, Taylor, W. Pat, Stuebing, Karla K., Fletcher, Jack M., Vaughn, Sharon |
المصدر: | Journal of Research on Educational Effectiveness. 2016 9(4):556-569. |
الإتاحة: | Routledge. Available from: Taylor & Francis, Ltd. 325 Chestnut Street Suite 800, Philadelphia, PA 19106. Tel: 800-354-1420; Fax: 215-625-2940; Web site: http://www.tandf.co.uk/journals |
Peer Reviewed: | Y |
Page Count: | 14 |
تاريخ النشر: | 2016 |
Sponsoring Agency: | Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (NIH) |
Contract Number: | P50HD052117 |
نوع الوثيقة: | Journal Articles Reports - Research |
Education Level: | Elementary Education Grade 4 Intermediate Grades |
Descriptors: | Educational Research, Research Design, Intervention, Statistical Analysis, Sampling, Pretests Posttests, Correlation, Sample Size, Elementary School Students, Grade 4, Reading Tests, Achievement Tests, Scores, Randomized Controlled Trials |
Assessment and Survey Identifiers: | Gates MacGinitie Reading Tests |
DOI: | 10.1080/19345747.2015.1086916 |
تدمد: | 1934-5747 |
مستخلص: | An appropriate estimate of statistical power is critical for the design of intervention studies. Although the inclusion of a pretest covariate in the test of the primary outcome can increase statistical power, samples selected on the basis of pretest performance may demonstrate range restriction on the selection measure and other correlated measures. This can result in attenuated pretest-posttest correlations, reducing the variance explained by the pretest covariate. We investigated the implications of two potential range restriction scenarios: direct truncation on a selection measure and indirect range restriction on correlated measures. Empirical and simulated data indicated that direct range restriction on the pretest covariate greatly reduced statistical power and necessitated sample size increases of 82%-155% (dependent on selection criteria) to achieve equivalent statistical power to parameters with unrestricted samples. However, measures demonstrating indirect range restriction required much smaller sample size increases (32%-71%) under equivalent scenarios. Additional analyses manipulated the correlations between measures and pretest-posttest correlations to guide planning experiments. Results highlight the need to differentiate between selection measures and potential covariates and to investigate range restriction as a factor impacting statistical power. |
Abstractor: | As Provided |
Number of References: | 17 |
Entry Date: | 2016 |
رقم الأكسشن: | EJ1115258 |
قاعدة البيانات: | ERIC |
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