Abstract
The contributions to this Special Issue illustrate research on several important types of environmental units, including psychiatric and substance abuse treatment programs, neighborhood block groups, and entire communities. They also exemplify alternative methodologies, such as assessing environments by relying on participants' appraisals, external observers' ratings, historical archives, and direct observation. I draw on these contributions and some of my own work to discuss four recurrent issues: (a) how to conceptualize environmental domains and dimensions; (b) how to understand environmental dynamics, that is, the interplay of environmental factors both within one setting and across settings; (c) how to comprehend the processes that link environmental factors to outcomes, especially with respect to the power and evanescence of environmental influence; and (d) how to use information about environments to monitor and improve them. Increased knowledge in these four areas is essential to help fulfill a major aim of community psychology: to understand social processes and improve intervention program outcomes.