The standard short increment sensitivity index (SISI) was given to 24 normal hearing subjects 10 times in two test sessions. For each subject the intensity difference hen was determined with a quantal method using the SISI apparatus. Although the group data indicated a statistically significant improvement in scores across presentations, the change was not clinically significant, in that the highest mean score continued to be “negative” in clinical interpretation. Four individual subjects, however, moved from initial scores in the negative or “questionable” range to “positive” scores with repeated presentations. Highest scores achieved by the subjects were found to be significantly related to intensity difference hen. The results suggest that the clinician must be aware of a potential for a clinically significant improvement in SISI score with practice on the part of some subjects.