Abstract Partly because of the field's efforts to deal first with the kinds of impacts that have been the most obvious and pressing, the traditional focus of social impact assessment has been on the impacts taking place during the most intensive phases of developmental activity. Recently it has become increasingly clear that a number of predictable, significant impacts take place both before and after the periods of most intense activity; these impacts are missed by social impact assessment approaches that are excessively narrow in focus. This paper offers a conceptual framework that is relatively simple but that deals with impacts both across time and across potentially affected systems of the human environment, doing so in such a way as to improve the promise of social impact assessment to become more nearly comprehensive.