Anticipated demographic changes in the United States adult population in the decade between the National Adult Literacy Survey (NALS) of 1992 and the National Assessment of Adult Literacy (NAAL), which is scheduled for 2002, were reviewed. Next, the implications of those changes for the NALS and NAAL were analyzed. The analysis focused on births, deaths, and international migration. Next, a demographic model of adult literacy proficiency was described that links changes in literacy proficiency to compositional and maturational changes in the adult population. Composition components were defined as changes over time in membership in the target population, whereas maturational components were defined as changes over time in the literacy proficiencies of given individuals who are in the target population at both time points. The model predicted increases over the decade in the mean literacy proficiency of both the foreign- and native-born adult populations and decreases in the percentages of each that are performing at the lowest level. (Eight implications of the model for the NAAL methodology were discussed, including implications related to the following issues: parallel population coverage in the NALS and NAAL assessments; adequate representation of minority and immigrant groups; and working with populations having limited English proficiency.) (MN)