Increased concern over the impact of acid deposition on natural resources has caused the proliferation of substantial research in the area of effects. Often overlooked is the synthesis of this vast body of information into a coherent picture to be used for assessment and policy analysis. Relationships among research projects frequently are poorly defined or lacking, and problems of spatial and temporal resolution are abundant. The acquisition and use of historical data, for example, water quality and fish stocking data, to determine trends over time is problematical. Assessments of aquatic effects will be made in 1985, 1987, and 1989 under the National Acid Precipitation Assessment Program. A procedure is presented which attempts to organize existing information over space and time. Problems are highlighted and information needs made apparent.