Fig. 4

Person-item threshold distributions showing targeting of item difficulties to person abilities, in logits, for: A the 12-item DTI-OS survey; B the six SM subdomain questions in the DTI-OS; and C the six FT subdomain questions in the DTI-OS. The difference in mean person abilities between experts and novices was significant for all three analyses (one-way ANOVA, P < 0.0001 in all instances). Abbreviations: DTI-OS, Diagnostic Thinking Inventory for Optometry Short; FT, flexibility in thinking; SM, structured memory