The workshop attracted wide interest among NEPS staff and members of other educational research projects located in Bamberg. After a short introduction to the principal application context of item response theory—that is, test development within the scope of educational studies—Johannes Hartig first outlined the key terms and basic ideas of probabilistic testing theory. Subsequently, he elaborated on statistical models of item response theory and especially on the dichotomous Rasch-model. Using the software Conquest, the participants themselves then had the opportunity to generate estimates on person- and item parameters on the basis of a predefined data set. Finally, Johannes Hartig explained in detail the software’s output file and gave some advice regarding the interpretation of results. Afterwards, he responded to individual questions from the participants. The National Educational Panel Study would like to sincerely thank Prof. Hartig for this informative and application-oriented workshop.