ERIC Number: ED163074
Record Type: Non-Journal
Publication Date: 1978-Mar
Reference Count: N/A
Accuracy of Estimating Two Parameter Logistic Latent Trait Parameters and Implications for Classroom Tests.
Kolen, Michael J.; Whitney, Douglas R.
The application of latent trait theory to classroom tests necessitates the use of small sample sizes for parameter estimation. Computer generated data were used to assess the accuracy of estimation of the slope and location parameters in the two parameter logistic model with fixed abilities and varying small sample sizes. The maximum likelihood procedure for estimating the parameters was compared to a method in which the observed relative frequencies were smoothed using an isotonic regression method prior to applying the maximum likelihood procedure. The isotonic method was considered promising because the smoothed relative frequencies yield more accurate estimates of the probability of correctly answering a test item given a particular level of the ability than do the observed relative frequencies. The results were presented in terms of variance and mean squared error of estimating the parameters. The results indicated that the isotonic procedure provided more accurate estimates of the location parameter whereas the maximum likelihood procedure provided more accurate estimates of the slope parameter. Since the isotonic method did provide for more accurate estimation of the location parameter, it was concluded that the isotonic method warrants further attention. The implications of the results for use with classroom tests were also discussed. (Author/CTM)
Publication Type: Reports - Research
Education Level: N/A
Authoring Institution: Iowa Univ., Iowa City. Evaluation and Examination Service.