The purpose of this study was the development and testing of a novel method for assessment of white blood cell (WBC) identification skills used in the field of Clinical Laboratory Sciences (CLS). A dual format exam was administered to both novices (students) and experts (laboratory professionals). Format 1 was similar to current assessment formats, simply presenting a series of single WBC images for identification. Format 2 applied principles of visual cognition, grouping WBCs for identification by patient and presenting multiple example images from the patient before requesting identification of individual cells. This novel exam format was intended to: (a) provide a contextualized visual background for single cell identifications, (b) mirror the process of WBC identification used in clinical practice, and (c) promote improved performance on difficult/atypical WBC identifications. The second phase of this study implemented qualitative methods to categorize the general cognitive processing styles used by novices/experts as either analytical or similarity-based. Cognitive processing styles were compared across the 2 levels of expertise as well as across exam formats. Statistical analyses did suggest that expert performance levels were significantly improved by the novel exam presentation format. Novice performance, however, was not significantly altered by exam format. Evaluation of response times indicated that expert response times were significantly shorter than novice response times in format 2, but not in format 1. In addition, analysis of qualitative data suggested that experts differed significantly from novices in their cognitive verbalizations for format 2, with experts making more statements at a higher cognitive level than did the novices. Format 1 verbalization differences were not found to be significant. Overall results indicated that the novel exam format invoked experts to implement similarity-based processing, allowing some identifications to be made at the level of the patient case, rather than simply at the feature identification level. Implications of this study include possible alterations to current certification/proficiency exam formats for questions requiring the visual identification of white blood cells. This study also suggests that using patient image sets as instructional stimuli may encourage the development of advanced cognitive processing skills in students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]