A series of research studies on the consistency of reading specialists' diagnoses of students with reading problems have indicated that clinical agreement has been astonishingly low. To investigate which factors seem to lead to consistency in clinical diagnosis, a study was conducted based on a theory of clinical problem solving called inquiry theory. This theory describes the ways in which a clinician approaches a case in order to diagnose the problems and recommend a program of remediation. Interactions are determined by the characteristics of the case material and by the clinician's memory and strategies. An assumption is that clinicians having had the same training will have greater similarities in their memories and problem solving strategies. Three reading disability cases--two actual cases, with the third being a slightly altered version of the first--were diagnosed by eight graduate students enrolled in a diagnostic practicum in a master's degree program for the reading specialist certification. Eight reading specialists in the field who had been trained in eight different institutions also diagnosed the same three cases. For the two cases that were actually the same, results showed a significantly higher intrasubject consistency among the graduate students than among the clinicians. While the intrasubject consistency was higher than intersubject consistency for the graduate student group (whose agreement was 100% consistent for the replicate cases), intersubject consistency was higher than intrasubject consistency for the reading specialist group. (HOD)