ERIC Number: ED236211
Record Type: Non-Journal
Publication Date: 1983-Aug
Reference Count: N/A
An Investigation of Methods for Reducing Sampling Error in Certain IRT Procedures.
Wingersky, Marilyn S.; Lord, Frederic M.
The sampling errors of maximum likelihood estimates of item-response theory parameters are studied in the case where both people and item parameters are estimated simultaneously. A check on the validity of the standard error formulas is carried out. The effect of varying sample size, test length, and the shape of the ability distribution is investigated. Finally, the effect of anchor-test length on the standard error of item parameters is studied numerically for the situation, common in equating studies, where two groups of examinees each take a different test form together with the same anchor test. The results encourage the use of rectangular or bimodal ability distributions, also the use of very short anchor tests. (Author)
Publication Type: Reports - Research
Education Level: N/A
Sponsor: Office of Naval Research, Arlington, VA. Personnel and Training Research Programs Office.
Authoring Institution: Educational Testing Service, Princeton, NJ.