Curriculum Compacting and Achievement Test Scores: What Does the Research Say?
Reis SM, Westberg KL, Kulikowich JM, Purcell JH · 1998
grade Brctdeveloper-ledunreplicated
Sample
336 high-ability students, grades 2-6, national US sample - an analysis subsample of the 783 students in the 1993 monograph
Population
High-ability students in rural, suburban and urban heterogeneous US classrooms
Design
The peer-reviewed journal report of the Curriculum Compacting Study, whose full design and results are recorded in the 1993 NRC/GT monograph (asmt-reis-1993-curriculum-compacting-study). Same randomised districts, same intervention, same out-of-level ITBS outcomes, smaller analysis sample.
Key findings
Teachers eliminated 40-50% of the curriculum for students who had already mastered it and achievement test scores did not differ significantly from controls; out-of-grade-level testing (one grade higher) was used explicitly to guard against ceiling effects. Set aside as a duplicate rather than as a second piece of evidence, because counting it separately would double-count one experiment.
Genetic confound
As for the 1993 monograph - district-level random assignment within a teacher-identified high-ability band.
Replication notes
Not an independent replication; it is the same study.
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Achievement after eliminating already-mastered curriculum | group difference | no significant difference between compacted and non-compacted students | standardized | end of school year | business-as-usual | end-of-treatment | domain-skill |
| Proportion of curriculum eliminated | % | 40-50% across content areas | standardized | across the school year | none | not-applicable | domain-skill |