The lack of a suitable research instrument on attitudes of elementary school children toward school and subject matters has limited the quality and extent of research on school attitudes. The Affective Reporting System was conceived to fill this need. It consists of two instruments--ME and What I Like Best (WILB), each possessing two versions: primary (grades 1-3) and intermediate (grades 4-6). The primary version measures attitudes toward reading, math, physical education, art and music; the intermediate version has added social studies and science. ME also has an attitude toward school scale. Both instruments measure essentially the same attitudes but in different ways--ME uses a three-point rating scale, while WILB uses the forced choice paired comparison technique. The results of a study of the reliability and construct validity of measures of attitudes are reported. Both tests were administered to 2,846 elementary school children. Internal consistency estimates of reliability for ME were reasonably high while WILB had less than satisfactory reliability estimates. Construct validity was clearly demonstrated for ME; WILB lacked construct validity when used in the primary grades sample and possessed moderate construct validity when used with the intermediate grades sample. It was concluded that these tests could efficiently provide reliable and construct valid measures of attitudes in a wide variety of applications. Instructions for administering, scoring, and interpreting ME and WILB, as well as forms of each test, are included. (Author/CP)