The Standard Evaluation Procedure (SEP) describes the procedures used by EPA to evaluate studies on the dissipation and movement of pesticide residues in the field. The SEP provides a data reviewer with important guidance in determining the acceptability of a terrestrial field dissipation study. Details of the proper study design are outlined and the relevance of each aspect of the study design pertinent to pesticide degradation is explained. The information is to be used by the reviewer as guidance in determining study acceptability. The document outlines the general theory of pesticide degradation and provides an overview of the methods used for calculating pesticide degradation rates and half-lives. Important points to consider in assessing the data and in drawing a conclusion about the dissipation and movement of pesticide residues in the field are discussed.