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A Comparison of School Mean Achievement Scores With Two Estimates of the Same Scores Obtained by the Item-Sampling Technique NICHD

Cahen, Leonard S.; Romberg, Thomas A.; Zwirner, Walter
Publication Year:
Report Number:
ETS Research Bulletin
Document Type:
Page Count:
Subject/Key Words:
National Institute for Child Health and Human Development (NICHD), Academic Achievement, Comparative Testing, High School Seniors, Item Sampling, Longitudinal Studies, Mathematics, National Longitudinal Study of Mathematical Abilities, Project TALENT


The accuracy of estimating test means for groups of twelfth grade students by the item-sampling technique examined. The subjects were from 35 twelfth-grade schools participating in the National Longitudinal Study of Mathematical Abilities. Half of the students in each school were assigned to a treatment condition where they took a complete 24-item mathematics test on the first day of testing and took item-sampled versions of the same test on the second day of testing. A second random group of students within each of the schools took the item-sampled version of the mathematics test on day 2 but did not take the complete version of the mathematics test on day 1. There was no evidence to indicate that taking the complete 24-item mathematics test influenced the performance on the item-sampled version on the second day of testing. Reasonably close estimates of mean performance were obtained from the item-sampling situation as compared to the means estimated from the conventional type of testing. The differences between the means estimated from conventional type testing and from item-sampling testing were found to diminish as a function of the number of students tested in the school (square root transformation). (Author/PR)

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