Earlier, Zhang Feyen (2005) proposed a qualitative framework for predicting how people working in a multitasking scenario switch between concurrent tasks with dynamically changing priorities. This paper describes a validation study of a computational model derived from this framework. Utilizing a general hierarchy of prioritization rules suggested by a companion empirical study, a model of a multiple task scenario built using a queueing network approach was compared to the empirical results. On all metrics considered, no means were found significantly different and the model replicated all but one of 54 task sequences demonstrated by human subjects. Comparisons to similar models utilizing only single prioritization rules revealed that the general hierarchy yielded substantially better predictions.