Answer: Many informant characteristics may be associated with scores on all kinds of questionnaires. Because any reports by any informants may be affected by characteristics of the informants, as well as by their own particular knowledge of the adult’s behavior, no single informant’s reports can provide a complete picture. It is desirable to construct a comprehensive picture of the adult from multiple sources and types of data. The answers to questions in the section of this chapter dealing with profiles provide guidelines for evaluating scores that are so low or high as to suggest gross distortions or errors. Chapter 9 of this Manual provides data on reliability and cross-informant agreement, while the Ages 18-59 Module displays comparisons and correlations between informants’ reports for a particular adult. The section of this chapter regarding profiles addresses lie scales.