Combined regression discontinuity and interrupted time-series design with instrumental variables¶
Research Method · All research methods
Evidence · 2 claims (2 for) · 1 study (1 causal),q3· 1 of 1 report an effect size · 2 claims rest on one study
Description¶
When a threshold-based policy changes conditions for non-targeted students too, a standard regression discontinuity cannot estimate the policy effect, only the enrollment effect. The authors show that "combining the two designs—a regression discontinuity and a time series design we address limitations that are usually inherent in each": the discontinuity provides a within-cohort check while cohort comparisons reveal effects on non-targeted students and on students far from the cutoff, with instrumental variables addressing imperfect compliance.
Accounts¶
- Combine regression discontinuity with interrupted time series (and instrumental variables) to estimate policy effects when the policy affects both targeted and non-targeted students: When a threshold-based policy changes conditions for non-targeted students too, a standard regression discontinuity cannot estimate the policy effect, only the enrollment effect. The authors show that "combining the two designs—a regression discontinuity and a time series design we address limitations that are usually inherent in each": the discontinuity provides a within-cohort check while cohort comparisons reveal effects on non-targeted students and on students far from the cutoff, with instrumental variables addressing imperfect compliance. (Takako Nomi et al. (2008))
Claims¶
- Double-dose algebra improved algebra test scores for targeted students just below the cutoff, with a larger post-policy gain than for students just above the cutoff [+M]
- The double-dose algebra policy adversely affected non-targeted above-norm students: their algebra grades declined and failure rates increased post-policy [+M]
Related Research Methods¶
-
Key Sources¶
- Takako Nomi and Elaine M. Allensworth. (2008). “Double-dose” Algebra as an Alternative Strategy to Remediation: Effects on Students’ Academic Outcomes. Consortium on Chicago School Research, University of Chicago. http://www.informaworld.com/smpp/content~db=all?content=10.1080/19345740802676739
Page metadata
| Field | Value |
|---|---|
type |
research-method |
id |
combined-regression-discontinuity-and-interrupted-time-series-design-with-instrumental-var |
title |
Combined regression discontinuity and interrupted time-series design with instrumental variables |
description |
When a threshold-based policy changes conditions for non-targeted students too, a standard regression discontinuity cannot estimate the policy effect, only the enrollment effect. |
status |
review |
generated |
by process:settle-candidates on 2026-10-09 |
trust |
unverified — no one has confirmed this page's content |
Frontmatter is the page's machine-readable record — see the Schema & Guide.