Respondent reflective effort was measured by item latencies or time taken in answering "easy" and "difficult" items. Easy items were defined as items to which the majority of respondents typically agreed to the statement or to which a majority of respondents typically disagreed with the statement. Difficult items were defined as items to which the majority of respondents selected the endorsement of "undecided." As predicted, item latencies on the Reflective Effort Index co- varied with item difficulty. Item latencies on a second and typical personality questionnaire were reported to covary with item length or number of words. Results of this study clearly support the validity of the Reflective Effort Index as a measure which differentiates subjects' responses to easy and difficult items. Implications of these results were discussed along with the relevance of these findings to a model for the prediction of reflective effort based on the interaction of level of item difficulty with different levels of motivations relevant to test taking.