Does spelling instruction make students better spellers, readers, and writers? A meta-analytic review - Graham, S; Santangelo, T (2014)
meta-analysis; evidence grade C

Writing to Read: A Meta-Analysis of the Impact of Writing and Writing Instruction on Reading. - Graham, S; Hebert, M (2011)
meta-analysis; evidence grade C

The Effects of Morphological Instruction on Literacy Skills - Bowers, PN; Kirby, JR; Deacon, SH (2010)
review; evidence grade C

A Meta-Analysis of Writing Instruction for Students in the Elementary Grades. - Graham, S; McKeown, D; Kiuhara, S; Harris, KR (2012)
meta-analysis; evidence grade C

Writing instruction improves students’ writing skills differentially depending on focal instruction and children: A meta-analysis for primary grade students - Kim, YSG; Yang, D; Reyes, M; Connor, C (2021)
meta-analysis; evidence grade C

Calderdale Excellence Partnership: IPEELL. Evaluation report and executive summary - Torgerson, CJ; Ainsworth, H; Bell, K; Elliott, L; Fountain, I; Gascoine, L; Hewitt, CE; Kasim, A; Kokotsaki, D; Torgerson, DJ (2018)
rct; evidence grade B

Genetic and environmental influences on writing and their relations to language and reading - Olson, RK; Hulslander, J; Christopher, M; Keenan, JM; Wadsworth, SJ; Willcutt, EG; Pennington, BF; DeFries, JC (2013)
twin-adoption; evidence grade B