Early research studying human performance on schedules of reinforcement indicated that scalloped response patterns (initial pausing followed by accelerating responding) were prevalent in fixed interval (FI) schedules, but later research has shown that scalloping is rare in humans. Problems with the description of response patterns include considerable variability in what was identified as a scallop and authors' exaggeration of the prevalence of scalloping. Methods of response pattern analysis, including the Mathematical Index of Curvature, interresponse time microanalysis, and visual inspection of cumulative records, are discussed. A technique of interval-by-interval classification of response patterns in cumulative records may improve descriptions of FI patterning. Cumulative record data from a published study (R. P. Bentall et al; see record 1986-08699-001) on schedule performance with infants are reanalyzed using the method to illustrate its application. (PsycINFO Database Record (c) 2016 APA, all rights reserved)