Data are used from the individualized math component of an operating educational system to validate the basic assumptions underlying EDSIM 1, a computer simulation model that traces the interaction of three probabilistic elements in an educational program and produces synthetic output regarding this interaction in terms of student time in the system. The three probabilistic elements traced in the model are the probability of passing a pretest, the probability of passing a post-test, and the unit service time distribution based on time spent to achieve mastery in a unit. Procedures are described for extracting, coding, and reducing the data for use in the model. Results indicate that although the model lacks ability to produce enough extreme results, variables used in the model are sufficient to describe time for completion of specific levels of instruction in an individualized curriculum. Appendices include a description of the computer program used in the simulation model and a mini-study which investigates factors predicting student performance for improvement of the EDSIM 1 model. (Author/CMV)