The Effect of Lapse of Time on Item Statistics for the Contemporary Affairs Test, Form 1952

Author(s):

Coffman, William E.

Publication Year:

1953

Report Number:

RM-53-05

Source:

ETS Research Memorandum

Document Type:

Report

Page Count:

12

Subject/Key Words:

Cooperative Contemporary Affairs Test, Difficulty Level, Item Analysis, Test Results, Time

Abstract

As a guide to the selection of items and as an aid in the interpretation of scores, it is desirable to know the effect of lapse of time on the item statistics. Do the items selected on the basis of pretesting remain "good" items throughout the following year? Can one safely infer that the differences in the norms for sophomores and those for freshmen reflect real differences in ability or are some of the differences the result of changes in the function of particular items over time? How well has the staff achieved its objective of making a test which is covering contemporary affairs without being subject to short time fluctuations? This report provides some data relative to these questions. It consists of a comparison of item analysis data for three samples -- the pretest sample of October 1951, a stratified sample of the sophomores who took the test in March 1952, and a sample of freshmen who took the test in September 1952.

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