Multiple Inference and Gender Differences in the Effects of Early Intervention: A Reevaluation of the Abecedarian, Perry Preschool, and Early Training Projects
Anderson, M. L. · 2008
grade Bcritiqueindependentmixednumbers spot-checked
Sample
299 across three trials (Abecedarian 111 + Perry 123 + Early Training 65)
Population
The three classic boutique early-childhood RCTs, reanalyzed jointly.
Design
Applies false-discovery-rate and family-wise-error corrections plus summary-index aggregation across the full outcome families, and tests cross-trial replication.
Key findings
Once you correct for testing dozens of outcomes, the Perry evidence base shrinks to two robust effects. Benefits are concentrated in FEMALES for attainment (pooled adult .27, SE .09) and are absent for males (-.05). This is the single most important corrective to the Perry/Abecedarian policy literature.
Counterfactual
Abecedarian controls got iron-fortified formula, free diapers and social services — NOT nothing. Perry controls got nothing.
Genetic confound
N/A (statistical reanalysis of RCTs).
Replication notes
The decisive multiplicity check. NOTE the balance: Anderson's own cross-trial replication verdict is 'In general, yes' for the female attainment effects — multiplicity kills the MALE and CRIME results, not the entire literature.
DOI / URL
10.1198/016214508000000841
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| PERRY standalone FDR reanalysis — the key result | outcomes surviving FDR | At q=.05 only TWO survive: early MALE IQ and FEMALE high-school graduation (3 more at q=.10) | mixed | adult | business-as-usual | adulthood | attainment |
| Cross-trial replication of Perry's extra outcomes | replication | 6 of 8 outcomes clearing naive p<.10 fail to replicate in Abecedarian or Early Training | mixed | adult | business-as-usual | adulthood | attainment |
| Pooled summary index, TEEN stage | ES (SE) | females .51 (.13); males .08 (.14); gender difference p=.029 | mixed | grade-6+ | business-as-usual | over-2yr | attainment |
| Pooled summary index, ADULT stage | ES (SE) | females .27 (.09); males -.05 (.11); difference p=.027 | mixed | adult | business-as-usual | adulthood | attainment |
| Adult Perry crime effects | FDR | No adult Perry crime effect rejects at q=.05 | mixed | adult | business-as-usual | adulthood | behaviour |
Cited by
- Perry Preschool and Abecedarian — what the famous studies actually establishmixedconf: mediumgc: low