The 2025 MAP Growth norms adopted a two-year, two-level piecewise mixed-effects design because two consecutive years of data are sufficient for within-year and adjacent-year growth norms¶
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Evidence · 1 study · designr2·q2
Currency · newest study 2025 · not yet checked against its sources · not reviewed by a person · recheck by 2028: tool and model accuracy changes quickly
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Reading the evidence codes
q is the design tier, i the impact, n the sample, and the kind with its r
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q2 i? Because the piecewise framework can model growth over two years and two consecutive years of data suffice for the required within-year and adjacent-year growth norms, the 2025 norms use a two-year piecewise model rather than the three-year designs of prior norms. → 2025 MAP Growth Norms Technical Manual 2025
Evidence¶
2025 MAP Growth Norms Technical Manual 2025¶
2025 MAP Growth Norms Technical Manual. (2025). HMH Education Company / NWEA. https://www.nwea.org/research/publication/2025-map-growth-norms-technical-manual/
q2 · i? · design · r2
Section 4.2 explains the shift from the three-year cohort design of the 2015 and 2020 norms to a two-year design; the manual states "Twoconsecutiveyearsofdataaresufficient toachievetheseoutcomes" and that the piecewise framework is capable of modeling growth over two years.
"Twoconsecutiveyearsofdataaresufficient toachievetheseoutcomes. Giventhatthethree-yearpiecewisemodeloutperformedboth compoundpolynomialmodels,andthepiecewiseframeworkiscapableofmodelinggrowth"
Discussion¶
Related Claims¶
- The 2025 MAP Growth norms were derived from one of the largest norming samples ever created, spanning 116,225,831 test events from 13,804,182 students in 29,720 schools across 7,000 districts over six testing terms — related
- Across 90 grade-subject-level conditions, the three-piece piecewise model showed the lowest deviance for 64% of student-level and 78% of school-level models, outperforming both compound polynomial candidates — related
- The proposed seasonal growth model combines polynomial terms for year-to-year growth with piecewise terms for within-year gains and losses — related
- The CP model fits seasonal achievement data better than a traditional polynomial growth model on RMSE, AIC, and BIC while reducing residual autocorrelation — related
Page metadata
| Field | Value |
|---|---|
type |
claim |
id |
two-year-piecewise-design-sufficient-for-map-growth-norms |
title |
The 2025 MAP Growth norms adopted a two-year, two-level piecewise mixed-effects design because two consecutive years of data are sufficient for within-year and adjacent-year growth norms |
description |
The 2025 MAP Growth norms adopted a two-year, two-level piecewise mixed-effects design because two consecutive years of data are sufficient for within-year and adjacent-year growth norms |
status |
review |
evidence_strength |
moderate |
newest_evidence |
2025 |
recheck_by |
2028 |
generated |
by process:wiki-ingest on 2026-10-08 |
trust |
unverified — no one has confirmed this page's content |
sources |
1 — 2025-map-growth-norms-technical-manual-2025 |
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