Abstract Sociopsychological variables, including attitudes, beliefs, values, and opinions, occupy a central place in emerging social impact assessment methodologies. Despite the attention that these perceptual concepts have received in the Social Impact Assessment (SIA) literature, there is little consensus on how they should be used. Four critical issues influence the utility of attitudes in the SIA process: (1) the location of attitudes in SIA research models, (2) the ubiquitous problem of attitude‐behavior predictability, (3) the “other variables”; problem, and (4) the measurement problem, i.e., the importance of measurement validity, reliability, and scalability. The authors first review the use of attitudes and perceptual measures in the SIA literature. This review reveals that while almost all authors of SIA models or methodologies recommend the inclusion of sociopsychological measures, the manner in which they propose these measures for use varies widely with most authors failing to specify whether such perceptual measures are being used as dependent, independent, or intervening variables. Most applications ignore the four critical issues listed above. After reviewing the current uses of sociopsychological measures in SIAs, the authors explain each of the four critical issues in depth and offer recommendations for changes and improvements in SIA practice. They conclude that while a sophisticated measurement literature has developed in the social sciences, the tendency among SIA practitioners is to ignore problems of sociopsychological measurement. Although the authors express concern about the lack of attention to measurement issues, they are convinced that the study of attitudes and opinions needs to have a central place in social impact assessment. Because sociopsychological research has become so complicated, however, the authors recommend that SIA practitioners enlist the help of qualified social psychologists when doing attitude/opinion studies, unless the practitioner is also a sociopsychologist. This article is a review intended primarily for SIA researchers who are not extensively trained in attitude research, but it also serves as a review and reminder for those scientists working primarily in the field of social psychology.