Confidence Intervals for True Scores Under an Answer‐Until‐Correct Scoring Procedure

Abstract

Under an answer‐until‐correct scoring procedure, many measurement problems can be solved when certain cognitive models of examinee behavior can be assumed (Wilcox, 1983). Point estimates of true score under these models are available, but the problem of obtaining a confidence interval has never been addressed. Two simple methods for obtaining a confidence interval are suggested that give good results when the sample size is reasonably large, say, greater than or equal to 20, and when true score is not too close to zero or one. A third procedure is suggested that can also be used to get slightly better results where again the sample size is assumed to be reasonably large and true score is not too close to zero or one. For small sample sizes or situations where true score is close to zero or one, a fourth procedure is described that always gives conservative results.