Defining and testing the assumptions used in current apparel grading practice

Grading is the process used to create sized patterns. Our research continues from the finding that grading practice is not based on anthropometric data (Schofield & LaBat, 2005). The focus of this research was to establish proportional rules, set increments, and assumptions that form the basis of grading. The grade rules for a basic bodice pattern from 17 sources were examined to identify grading practice. Seven grading assumptions were identified and tested using regression analysis on body measurements of the upper torso from the 1988 Anthropometric Survey of U.S. Army Women. None of the assumptions were supported. Use of these assumptions results in sized garments that do not reflect the measurements and proportions of the human body. A comparison was made between a pattern graded with traditional grade rules and another graded with research generated experimental rules. New criteria for evaluating graded patterns are presented.