A clear variable coordinate lesson produced higher achievement than an unclear lesson with the same concept structure on all five measures¶

Claim · All claims
Evidence · 1 study · causal r2 · q3
Currency · newest study 1991 · not yet checked against its sources · not reviewed by a person
Evidence quality · No study behind this claim is a peer-reviewed article with a DOI: it rests on an ERIC document (a report, conference paper or thesis). It is kept because 2 design pages cite it; treat it as a lead to check, not an established finding.

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 i? The Clear/Var./Coord. group achieved significantly better than the Unclear/Var./Coord. group on definition, example identification, key words, nonexamples, and application. → Snyder 1991

Evidence¶

Snyder 1991¶

Snyder, Stephen; Bushur, Lori; Hoeksema, Pam; Olson, Mark; Clark, Shawn; Snyder, Jill. (1991). The Effect of Instructional Clarity and Concept Structure on Student Achievement and Perception. https://eric.ed.gov/?id=ED331809

q3 · i? · p-values only, no effect size printed · causal · r2

Dunn-Sidak multiple comparison tests in the Results section of the 2x3 factorial experiment. The article reports the clear variable coordinate group beat the unclear group on all five achievement sections, with p<.01 on four and p<.05 on nonexamples.

"the Clear/Var./Coord. concept group achieved significantly better than students who receivedan unclear presentation with the same concept structure (Unclear/Var./Coord.).This achievement difference held true on the definition (p<.0l), identification of examples of the concept taught (p<.0l)"

Studies bearing on this claim¶

Does a clearly presented lesson beat an unclear one, and when does clarity matter most? This table gathers the studies behind this claim and the 6 narrower claims that bear on it: 3 distinct studies (2 qualitative, 1 causal), q2–q3, 1 of 3 with an effect size coded. One row per study, codes as each entry records them; no effect is averaged and no verdict is drawn. Built by scripts/synthesize_claim.py from eval/synthesis/; a row that looks wrong is fixed on the claim it comes from.

Study	Design	Effect as recorded	Bears on this claim through
Snyder 1991	q3 · causal · r2	i?; i2	this claim; Each positive clarity move (keys, links, framing, focusing, examples) correlates positivel (supports); Under unclear presentation, a more complex concept structure lessens students' ability to (supports); Clarity matters less as concept structure becomes simpler: no significant clear-vs-unclear (qualifies); Students accurately perceive differences between clear and unclear lessons regardless of c (qualifies)
clarity-1	q2 · qualitative · r?	i?	Definitions, checkpoints, and staged pacing improved conceptual clarity for novice program (supports)
Suleiman 2026	q2 · qualitative · r1	i?	Students responded most positively to projects that felt authentic and were organized in a (supports)

Discussion¶

Page metadata

Field	Value
`type`	`claim`
`id`	`clear-variable-coordinate-beats-unclear`
`title`	`A clear variable coordinate lesson produced higher achievement than an unclear lesson with the same concept structure on all five measures`
`description`	`A clear variable coordinate lesson produced higher achievement than an unclear lesson with the same concept structure on all five measures`
`status`	`review`
`evidence_strength`	`moderate`
`newest_evidence`	`1991`
`generated`	by `process:wiki-ingest` on `2026-09-25`
`trust`	unverified — no one has confirmed this page's content
`sources`	1 — `snyder-1991`

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