A Solution of the Conditional Estimation Problem for Long Tests in the Rasch Model for Dichotomous Items

Estimation procedures for the item parameters in the Rasch model for dichotomous items are briefly reviewed, and it is concluded that the statistically correct conditional maximum likelihood (CML) method has not been used because of numerical problems. A solution to these problems is presented which allows a rapid computation of the CML estimates also for long tests. It is pointed out that there may be only small differences between the numerical values of the CML estimates and other estimates, but that the CML approach has decisive advantages in the construction of statistical tests of goodness of fit.