Lance, C. E., Butts, M. M., & Michels, L. C. (2006). The sources of four commonly reported cutoff criteria what did they really say?. Organizational research methods, 9(2), 202-220.
"Comparing this section to citations to it, we note several things. First, we suspect that most authors who cite Nunnally’s .70 reliability criterion would not agree that they are trying to save time and energy in an early stage of research by using measures that have only modest reliabilities. Rather, we suspect that most researchers would claim to be conducting basic (or
perhaps applied) research, for which purpose Nunnally clearly recommended a reliability standard of .80. Carmines and Zeller (1979) made a similar recommendation: “As a general rule, we believe that reliabilities should not be below.80 for widely used scales” (p. 51). Thus, our second point is that .80, and not .70 as has been attributed, appears to be Nunnally’s recommended
reliability standard for the majority of purposes cited in organizational research."