This guidebook concentrates primarily on describing the impact-assessment component of the Elementary and Secondary Education Act (ESEA) Title I evaluation and reporting system for users of the system. Three general evaluation models are presented, along with implementation information for each. The first model, a norm-referenced design, may be implemented using norm-referenced or non-normed tests; if norm-referenced tests are chosen, a pretest-posttest design is required. The second model, a control group design, calls for either a normed or non-normed test to be given to treatment and control groups within a pretest-posttest design; however, if a non-normed test is used, a nationally normed test must also be administered to the treatment group sometime during the school year. The third model, a special regression design, can also use norm-referenced or non-normed tests within a pretest-posttest design. The models all focus on obtaining as clear and unambiguous an answer as possible to the question of how much more the students learned by participating in the Title I project than they would have learned without it. Regardless of the model used, cognitive achievement gains are expressed in terms of a common metric--the normal curve equivalent. Ways of measuring gains in normal curve equivalents are discussed. Information is provided on the collection of data pertinent to five other aspects: (1) participation of services by type to public and non-public school students; (2) Parent Advisory Councils; (3) programming costs; (4) program personnel; and (5) training for teachers and teaching aides. Seven figures and one data table are included. (TJH)