The roles of handwriting and keyboarding in writing: a meta-analytic review

Meta-analysis of studies relating handwriting and keyboarding fluency to writing performance (Reading and Writing 32(1), 33-63)

School-age writers across the primary and secondary range

Meta-analysis of CORRELATIONS, not of interventions - it pools the association between transcription fluency (handwriting, keyboarding) and writing performance, plus the association between handwriting and keyboarding speed. Graded D under METHODOLOGY because cross-sectional correlational work is exactly the design class the archive's premise treats as presumptively confounded: children who form letters fluently at seven are not randomly assigned to that state. Included as the quantitative statement of the correlational bottleneck claim, with that caveat attached, not as evidence that raising transcription fluency raises writing.

Handwriting fluency contributes to writing significantly and consistently, and is significantly related to specific writing measures including writing quality, writing fluency and substantive quality. Handwriting and keyboarding fluency are themselves significantly related, particularly on speed, with an expected effect size of r = .43 for the correlation between handwriting and keyboarding speed. That last number is the useful one for a practical decision: a child who is slow with a pencil is, on average, also slow at a keyboard, so switching modality is not a workaround for a transcription bottleneck.

High. This is a correlational synthesis. Handwriting fluency, keyboarding speed and writing quality are all substantially heritable and all load on the same underlying language and motor capacities (Olson et al. 2013 finds correlated genetic influences across writing measures), so the pooled correlations are an upper bound on any causal path and cannot license a claim that training transcription raises composition.