Table 1.

Participant Demographics

General information	Numbers participants | observations	137 | 441
	Number observations per participant	3 ± 1
	Age at literacy-related subskill and cognitive testing (months)	63 ± 5.3
	Age at decoding/word reading testing (months)	82 ± 6.4
Covariates	Biological sex (F/M)	73/64
	Maternal education (years)	17 ± 2.1
	Cohort ([New England]/Calgary)	80/57
	Family history of reading difficulty (+/-)	40/40
	Home literacy environment (a.u.)	0.037 ± 0.41
Literacy-related subskills	Phonological processing standard score	106 ± 14
	Oral language standard score	113 ± 13
Decoding/word reading	Word attack standard score	112 ± 14
	Word identification standard score	110 ± 17
Cognitive abilities	Nonverbal general cognitive ability	106 ± 13