Treatment of handwriting problems in beginning writers: Transfer from handwriting to composition.

144 first-graders (screened from almost 700) randomly assigned to 1 of 6 conditions

First-grade children (roughly ages 6-7) identified as at risk for handwriting problems

The single most directly applicable design in this tranche to the "three children aged 5-7" case, and it is worth stating the delivery detail precisely: treatment was delivered TO GROUPS OF THREE, meeting twice a week in 20-minute sessions until 24 lessons were completed. Five groups received 10 minutes of a different kind of handwriting instruction (varying whether children copied, used numbered stroke arrows, and/or wrote from memory); the sixth was a CONTACT CONTROL receiving 10 minutes of phonological awareness training. All six groups then composed and shared their writing for 10 minutes. Because every arm writes and every arm gets adult attention, this isolates the letter-formation content. Graded C rather than B: 144 children across six arms is ~24 per cell, outcomes are researcher-administered, and the design is unregistered and now nearly thirty years old.

Converging evidence across multiple measures identified combining numbered stroke arrows with memory retrieval as the most effective treatment for improving both handwriting and composition - i.e. the effective ingredient is the letter-formation procedure, not writing practice volume or adult time, both of which the contact control also received. The composition transfer is the headline claim, and it is the one that the newer primary-grades meta-analysis (Kim et al. 2021) does not reproduce across the wider transcription literature.

Low. Random assignment from a screened pool; all arms are matched on adult contact and on time spent composing.