The Guide is a tool for practitioners at all levels - social scientists, agency employees, community leaders, volunteers - to complete social impact assessments (SIAs) efficiently and effectively. The Guide is a how-to manual that provides the users with a step-by-step process easily followed by persons with minimal social science training. The Guide is organized into three sections: Chapters 1-6 provides the background, a short history, the conceptual model, the SIA scoping process and an explanation as to how to obtain data to measure SIA variables. Chapters 7-11 correspond to the five categories of SIA variables - population change, community and institutional arrangements, communities in transition, individual and family impacts and community infrastructure needs. Chapters 12-13 provide worksheets for summarizing SIA variables, and how resulting data may be used in the SIA mitigation/enhancement process.