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Simulation Study on the Performance of the Simple Difference and Covariance-Adjusted Scores in Randomized Experimental Designs.

Title: A Simulation Study on the Performance of the Simple Difference and Covariance-Adjusted Scores in Randomized Experimental Designs.
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Name(s): Petscher, Yaacov, author
Schatschneider, Christopher, author
Type of Resource: text
Genre: Text
Date Issued: 2011-04-01
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Research by Huck and McLean (1975) demonstrated that the covariance-adjusted score is more powerful than the simple difference score, yet recent reviews indicate researchers are equally likely to use either score type in two-wave randomized experimental designs. A Monte Carlo simulation was conducted to examine the conditions under which the simple difference and covariance-adjusted scores were more or less powerful to detect treatment effects when relaxing certain assumptions made by Huck and McLean (1975). Four factors were manipulated in the design including sample size, normality of the pretest and posttest distributions, the correlation between pretest and posttest, and posttest variance. A 5 × 5 × 4 × 3 mostly crossed design was run with 1,000 replications per condition, resulting in 226,000 unique samples. The gain score was nearly as powerful as the covariance-adjusted score when pretest and posttest variances were equal, and as powerful in fan-spread growth conditions; thus, under certain circumstances the gain score could be used in two-wave randomized experimental designs.
Identifier: FSU_pmch_26379310 (IID), 10.1111/j.1745-3984.2010.00129.x (DOI), PMC4569012 (PMCID), 26379310 (RID), 26379310 (EID)
Grant Number: P50 HD052120
Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569012.
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_pmch_26379310
Owner Institution: FSU
Is Part Of: Journal of educational measurement.
0022-0655
Issue: iss. 1, vol. 48

Choose the citation style.
Petscher, Y., & Schatschneider, C. (2011). A Simulation Study on the Performance of the Simple Difference and Covariance-Adjusted Scores in Randomized Experimental Designs. Journal Of Educational Measurement. Retrieved from http://purl.flvc.org/fsu/fd/FSU_pmch_26379310