This exploratory study examined differences in the problem representations of a case-based situation by expert and novice instructional designers. The experts and half of the novices (control group) received identical directions for case analysis, while the other novices (treatment group) received additional guidelines recommending analysis strategies that experts tend to use. After participants' case analyses were scored on four dimensions of problem representation, a Wilcoxon nonparametric test was performed. Significant differences were noted between experts and control novices on the total score and on two dimensions of problem representation. Treatment novices did not differ significantly from experts, while control and treatment novices differed significantly on one dimension. Implications for future research and practice are discussed. (Contains 4 tables, 2 exhibits, and 1 figure.)