Research was conducted to illustrate how the profile approach to measurement could be used to define "standardized fits" between literacy task difficulty and adult proficiency. To provide understanding of this type of standard, the study began by comparing clothes anthropometry to educational measurement; in the former, the concern is with fitting clothing size to human size, whereas in the latter the concern is with fitting task difficulty with adult proficiency. To optimize such fits, researchers proposed that, just as a set of variables (for example, neck and sleeve size) and their constructs (length measured in inches) provides a common means for interpreting and relating clothes size to human size, there must be a similar means of interpreting and relating task difficulty to human proficiency. Some variables and their constructs can be identified and validated that characterize both task difficulty and adult proficiency on the prose, document, and quantitative scales of the Department of Labor's Workplace Literacy Assessment and the recent National Adult Literacy Survey. Similar to the anthropometric categories of "small,""medium,""large," and "extra-large" in clothing sizes, five levels of task difficulty and adult proficiency were described and validated on the two assessments' three literacy scales. The study concluded by considering how these five levels serve as useful standardized definitions of "growth space," which, in turn, provides an important basis for designing enhanced computer-based measurement and instructional systems. (Contains 72 references.) (Author/KC)