Public policy making, in particular environmental impact assessment, relies not only on scientific aspects of technology, but also on evaluation of social values and policy decision and judgments making. This paper explores into how to incorporate science, values, and judgments into the process of environmental impact assessment, in order to propose a framework for environmental impact assessment as a basis for policy considerations by environmental protection agencies. The theoretical foundations include social choice theory, social judgment theory, and multi-attribute evaluation methods. Social choice theory depicts the democratic mechanisms for environmental policy making; social judgment theory explains how science and values could be integrated into policy making and feasibility; multi-attribute evaluation methods establish collective decision-making techniques for selection of development projects. Using hillside development cases, I show how this framework works in reality.