This meta-analysis explored how measuring progress toward long- versus short-term goals relates to contrasting outcome measures of student achievement. Twenty-one controlled studies, that provided sufficient data for the calculation of effect size, were coded in terms of measurement method (toward long- versus short-term goals) and type of achievement outcome (probe-like versus global achievement test). Analogues to analysis of variance conducted on weighted unbiased effect sizes (UES's) indicated an interaction: when progress was measured toward long-term goals, UES's on global measures were higher than on probe-like outcomes; when progress was measured toward series of short-term goals, the reverse was true. As demonstrated in this meta-analysis, short-term goal measurement may be misleading. Students may master a series of instructional objectives, even though progress may be limited on more global indices of achievement which better represent the true desired outcome performance. Consequently, for special education teachers who monitor mastery of short-term objectives, caution may be in order: curriculum-based assessment of long-term goals may represent a necessary supplementary strategy for validly assessing pupil progress. References, tables, figures, and a list of reports included in the meta-analysis are appended. (Author/PN)