From 1974 through 1978, three methods of assessing Scottish high school students' (O level) English achievement were studied: (1) Ordinary (O level) examinations; (2) assessment of writing skills (folio assessment); and (3) criterion referenced tests developed by the Scottish Council for Research in Education (SCRE) to measure the objectives of the Ordinary grade English course. Ten schools supplied complete data, and one school supplied partial data. General conclusions of the research favored the O-grade English examination because it is a well-tried method; it is used nationwide, ensuring comparability of standards; and teachers are satisfied with it. Problems with the O-grade examination include intermarker inconsistency and lack of fine discrimination among large numbers of average students. Although folio assessment could be more directly related to particular courses, inservice education in grading practices would be necessary, marker inconsistency would be present, and some teachers would be reluctant to take on the work involved. The criterion assessment would serve as an independent criterion with which to compare folio and O-grade evaluations. However, the study did not include an assessment of interpretation demanded by this method. Various appendices are attached, including some of the criterion tests and the teacher attitude questionnaire. (MH)