This paper discusses the use of telephone surveys as a substitute for, or addition to, the use of door-to-door surveys in assessing adult literacy ability. Part 1 addresses issues of validity in adult literacy assessment, including the concepts of construct or inferential validity and action or use validity. Part 2 is a review of related research that has used telephone and mail surveys to assess the cognitive abilities of adults. Part 3 discusses the theoretical model of literacy that the National Adult Literacy Survey (NALS) and International Adult Literacy Survey (IALS) have used and how that model can be modified to incorporate a developmental and componential model of literacy that also includes the oral language aspects of literacy given in the Adult Education and Family Literacy Act of 1998. Part 4 addresses several issues about the use of telephone and mail surveys, including concerns about using these survey methods in such a way as to make continuity in trend data from previous surveys of adult literacy possible. Appendixes include 69 references and a summary of an empirical study of the proposition that at a certain stage adults' comprehension of language can be assessed as well by listening as by reading. (Author/YLB)