Relationships Among Achievement Level Estimates from Three Item Characteristic Curve Scoring Methods.

Results for all data sets showed a high degree of similarity among parameter value estimates for the one- and two-parameter data, with slight decreases in correlations as information on the discrimination parameter was used in scoring. In general, however, the adaptive test data were less likely to result in convergence failures than were the conventional test data. The data also illustrated how each of the three scoring methods tend to utilize ICC parameter information in arriving at parameter value estimates and the relationships of these estimates to a number-correct scoring philosophy. Advantages and disadvantages of each of the scoring methods are discussed. It is suggested that future research examine the relative validities of scoring methods and model combinations.