OCD symptoms, even early in the illness, might influence problem-solving efficiency rather than problem-solving accuracy measured within a time limit. A controlled study of adults with OCD (1) demonstrated no between-group differences in number of responses, rate of perseverative responses, and rate of perseverative errors on the Wisconsin Card Sorting Test. However, OCD patients required significantly more time to respond to each trial and to complete the entire test. Careful consideration suggests that within our group of frontal lobe tests, we can make distinctions between those that were timed but brief and highly structured (e.g., Stroop Color/Word Test, Trail Making Test B, Controlled Oral Word Association test) and those that had no obvious time constraints but required deductive reasoning (e.g., Tower of Hanoi, Wisconsin Card Sorting Test). The latter tests emphasize rule acquisition and the problem-solving process, whereas the former require clearly defined responses (e.g., ink color, alternation between numbers and letters) while inhibiting other clearly defined but inappropriate responses. One explanation for our null results may be that we failed to measure problem-solving efficiency during the completion of unstructured problems that require, among other things, the discovery of rules.