Table 3. Study 2: Average stability of language by groups.

Average stability represents the mean of correlation coefficients controlled for child age only. Average stability controlled for covariates represents the mean of partial correlations controlled for child age, nonverbal intelligence, sociability, and maternal age and education. The relatively small sample sizes in the very preterm and autism groups contributed to somewhat diminished precision in the point estimates of average correlation and, thus, wider 95% CIs.

	Average stability		Average stability controlled for covariates
	Point estimate	95% CI	Point estimate	95% CI
Typical (n = 4111)	0.56	0.54–0.58	0.46	0.43–0.48
Moderate-late preterm (n = 435)	0.59	0.53–0.65	0.49	0.41–0.55
Very preterm (n = 51)	0.59	0.37–0.74	0.47	0.22–0.66
Dyslexia (n = 322)	0.52	0.44–0.60	0.44	0.34–0.52
Autism (n = 89)	0.65	0.50–0.75	0.54	0.38–0.68
Hearing impairment (n = 221)	0.55	0.45–0.63	0.47	0.36–0.57