This study investigated the importance of instrumental use of curriculum-based measurement (CBM) to planning effective reading programs. Participants were 53 mildly handicapped students and their 29 teachers who had been assigned randomly to CBM and control groups. Teachers implemented their CBM or control treatments for 15 weeks. After the treatment period, student records were inspected to divide the CBM participants into two implementation groups. The CBM-measurement only group comprised 15 students and 9 teachers; these teachers measured students' reading performance as required but did not use the assessment information to structure students' reading programs. The CBM-measurement with evaluation group comprised 21 students and 12 teachers; these teachers measured student performance and used the assessment information to design instructional programs. Analysis of variance revealed that, compared to the control group, pupils in the measurement with evaluation group achieved better than students in the measurement only group. Implications for instructional assessment activities are discussed. C URRICULUM-BASED ASSESSMENT refers to the evaluation of instructional needs through ongoing measurement of student performance within the local school curriculum (Gickling, 1981;Tucker, 1987). This generic term subsumes a variety of alternative practices. Some are relatively informal and highly idiosyncratic, such as the tests teachers devise and administer within their classrooms for assessing student mastery of material and assigning grades. Other versions of curriculum-based assessment are more standardized and technically refined. One example of a well-developed curriculum-based assessment system is Curriculum-Based Measurement (CBM).CBM has been implemented and researched systematically over the past 15 years, with assessment procedures derived from an ongoing, applied research program (e.g., Deno, 1985; Deno & Fuchs, 1987). CBM delineates standarized measurement procedures for drawing testing material from reading, spelling, written expression, and math curricula, and for administering and scoring those tests (Deno, 1986; Deno & Fuchs, 1987; Shinn, in press). These standardized measurement procedures can be applied reliably to local school curricula, and the same set of CBM procedures can be used validly for a variety of assessmentrelated purposes (Germann & Tindal, 1985).For example, CBM appears to be psychometrically tenable for traditional, norm-referenced assessment functions, including the screening, referral, and identification of students with learning problems (Marston, Mirkin, & Deno, 1984; Shinn, Tindal, & Stein, 1988). Studies also have investigated the use of CBM for additional assessment purposes, such as the evaluation of school programs and the formulation of instructional plans. Researchers have demonstrated that CBM can be used to improve the scope and usefulness of program evaluation decision (Germann & Tindal, 1985) and to develop instructional plans that enhance student achievement (Fuchs, Deno,...