An experimental study of task design expertise is reported wherein a set of 12 mathematics tasks were sorted by specialist designers of mathematics tasks and by experienced mathematics teachers without specialist design experience. Contrary to the frequent finding of increasing conceptual depth with increasing expertise, conceptual depth did not differ between groups. Teachers sorted on the basis of mathematical content earlier than designers, and were more specific in their content-based categories. Designers produced more sorts than teachers and were more individualistic in their sorting. These findings suggest that domain expertise does not necessarily impair creative problem solving, as has been suggested in other studies. Instead, expertise includes the ability to shift perspectives with respect to the domain.