Differences in Iowa Tests of Basic Skills scores were compared between Rhode Island fourth and eighth graders, and between parochial and public school students. This final report is organized in four major sections, plus appendices. The interviewing component activities are described in the first section, and clustered under six areas: convening an Advisory Council, selecting schools and obtaining permission for the interviews, developing interview questionnaires, training interviewers, conducting the interviews, and tabulating and analyzing the data. The other three sections describe the focus areas of the study. The school setting factors component dealt with the school testing procedures, parent attitudes toward school, organizational environment, and curriculum and instruction variables. The interaction of socioeconomic status and achievement, and other specific demographic variables are discussed in the population factors component. A variety of tables display data related to these population characteristics. Psychometric and test-intrinsic factors include scaling issues and an analysis of the testing data. The appendices include a list of the sample schools, the questionnaire and interview forms, and a 5-item bibliography which accompanies the population factors component. (The conclusions of this study are summarized in TM 007 493). (BW)