“…Earlier work by Zimmerman (1989Zimmerman ( , 1990 and others (e.g., Gerschick, Israel, & Checkoway, 1990;Rappaport, 1981Rappaport, , 1987Swift & Levin, 1987) provided the conceptual foundation for Zimmerman and Zahniser's (1991) study, which initially developed the SPCS by clarifying and linking literature and measures of SPC to PE. The SPCS was intended to be an integrated measure, drawing on items from 10 instruments designed to assess related aspects of SPC, such as political efficacy (Craig & Maggiotto, 1982), perceived competence (Florin & Wandersman, 1984), locus of control (Levenson, 1974), and sense of mastery (Pearlin, Menaghan, Lieberman, & Mullan, 1981). The 17 items included in the SPCS were selected on the basis of several validity criteria.…”