ERIC Number: ED307328
Record Type: Non-Journal
Publication Date: 1989-Mar
Reference Count: N/A
The Effects on Parameter Estimation of Correlated Dimensions and a Differentiated Ability in a Two-Dimensional, Two-Parameter Item Response Model.
Batley, Rose-Marie; Boss, Marvin W.
The purpose of this study was to assess the effects of correlated dimensions and differential ability on one dimension on parameter estimation when using a two-dimensional item response theory model. Multidimensional analysis of simulated two-dimensional item response data fitting the M2PL model of M. D. Reckase (1985, 1986) was conducted using the MIRTE analysis program. Six data sets (2,000 ability vectors by 104 items) were generated to satisfy two conditions of the distributions of the ability dimensions and three different degrees of correlation between two abilities. The six data sets (two distributions times three correlations) and analyses were replicated 100 times each. Summary statistics on the 100 replications were used to assess the effects of the degree of correlation between ability dimensions and differential ability on the second dimension. Results indicate that the MIRTE program recovers the structure of a multidimensional correlated space better than do previous estimation programs, especially in the cases in which the items were multidimensional in themselves. However, the MIRTE program tended to underestimate the degree of correlation between the ability dimensions, but it did not force orthogonality on the dimensions. Because of the limitations imposed on any single body of research in terms of research design, some alternative situations need to be studied. Future investigations should assess the accuracy of estimation procedures when a guessing parameter and different latent space structures are included. (TJH)
Publication Type: Reports - Research; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A