What can I do if RUMM2030 advises that 'overflow' has occurred?


Overflow is the term used to indicate that a computer is unable to proceed with the processing of data.  It occurs when values become so small that it is impossible for the computer to conduct normal algebraic processes due to serious lack of precision.  Overflow can occur with Rasch analysis using RUMM2030 during the estimation of item and person parameters and for test of fit statistics:


Andrich, D. & Luo, G. (2003).  Conditional Pairwise Estimation in the Rasch Model for Ordered Response Categories using Principal Components. Journal of Applied Measurement, 4(3), 205-221.

Andrich, D. & Luo, G. (2004).  Estimating parameters in the Rasch model in the presence of null categories. Journal of Applied Measurement, .