The effects of instruction on the singing ability of children ages 5 to 11: A meta-analysis

k = 34 studies

Children aged 5-11 receiving singing instruction; outcomes are singing accuracy (pitch-matching, song accuracy, use of singing voice)

Restricted by design to pretest-posttest or posttest-only QUASI-experimental studies - the author states this inclusion rule explicitly - so there is no randomised evidence inside the pooled estimate. That is the ceiling on the grade. Useful precisely because the outcome is the taught skill itself, measured with published singing-accuracy instruments (Boardman and similar) rather than a researcher-invented scale.

Overall mean effect of instruction on singing ability g = 0.43 across 34 studies. Mean effects by moderator ranged from trivial to moderate. FEEDBACK produced the largest effect among teaching conditions; 8-year-olds showed the largest effect among age bands; song accuracy was the most responsive measured task. Boys and girls improved similarly. The author's conclusion is that singing interventions improve singing ability more than traditional song-singing and more than no music instruction at all, and that the 5-8 window is where intervention matters most.

Not addressed. Individual differences in singing accuracy are substantially heritable, but the contrast here is instruction versus less instruction within samples, so the relevant threat is selection into the treated groups rather than heredity per se - and with no randomised studies in the pool that threat is unmanaged.

No independent replication of this meta-analysis located; the singing-accuracy literature it pools is small and largely North American.