Claims

Ladders to Literacy shows potentially positive effects on alphabetics, with an average improvement index of +25 percentile points and a domain average effect size of 0.69

Claim · All claims
Evidence · 1 study · quant-synthesis r2 · q3 · i2 medium
Currency · newest study 2007 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims

Reading the evidence codes

q is the design tier, i the impact, n the sample, and the kind with its r the rigour judged within that kind: what each code means.

This claim: no standardized effect is recorded in observations/ for it yet, so no benchmark reading is possible.

q3 i2 Four studies meeting WWC standards with reservations examined alphabetics, and Ladders to Literacy was rated as having potentially positive effects; the average improvement index of +25 percentile points (range +8 to +47) and the domain average effect size of 0.69 come from the three studies with computable effect sizes (the fourth, Fuchs et al. 2001, had none). → What Works Clearinghouse 2007

Evidence

What Works Clearinghouse 2007

What Works Clearinghouse, U.S. Department of Education. (2007). Ladders to Literacy for Kindergarten Students. WWC Intervention Report. https://ies.ed.gov/ncee/wwc/InterventionReport/259

q3 · i2 · quant-synthesis · r2

WWC synthesis of four studies (760 kindergarten students, more than 14 elementary schools) meeting standards with reservations. The report states "The average improvement index for alphabetics is +25 percentile points across three studies"; the printed domain average effect size for alphabetics is 0.69, and the rating was potentially positive effects.

"The average improvement index for alphabetics is +25 percentile points across three studies, with a range of +8 to +47 percentile points across findings."

Discussion

Page metadata
Field Value
type claim
id ladders-to-literacy-potentially-positive-alphabetics
title Ladders to Literacy shows potentially positive effects on alphabetics, with an average improvement index of +25 percentile points and a domain average effect size of 0.69
description Ladders to Literacy shows potentially positive effects on alphabetics, with an average improvement index of +25 percentile points and a domain average effect size of 0.69
status review
evidence_strength moderate
newest_evidence 2007
source_checked 2026-10-20
generated by process:wiki-ingest on 2026-10-07
trust unverified — no one has confirmed this page's content
sources 1 — what-works-clearinghouse-2007

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