This article is the last in a series of four. Each looks at one step in the evaluation and planning process: description, investigation, analysis and decision (see Kenyon 1983). Participation in all steps is the ideal. This paper looks at decision. Three sections look at decisions about changes to address needs or problems; strategy decisions and deciding among alternative strategies; and evaluation decisions, or the measurement of results against objectives. Examples are drawn from projects in a number of countries, illustrating processes of community participation in decision making and the use of visual representations in assisting the making of decisions.