Abstract
Children with poor reading comprehension tend to have oral language weaknesses, suggesting that poor language in the early years is a proximal cause of later reading comprehension difficulties. Yet, longitudinal studies have not succeeded in reliably predicting which children go on to have comprehension weaknesses (CW), and evidence comprises small sample sizes and a narrow focus on language in isolation. In this registered report, we examined early predictors of later outcomes in 879 children with CW identified at 9 years in the Avon Longitudinal Study of Parents and Children. Study 1 showed that these children had poorer language at 24 and 38 months (but not 15 months) than peers who did not go on to develop reading difficulties (n = 4516). However, preschool language ability was a poor predictor of individual outcomes, which was not improved by accounting for the language and communication environment. Study 2 used a multiple risk approach to ask whether breadth (number) or depth (severity) of risk factors predicted reading outcomes in a subsample of 125 children with CW and 561 typically developing readers. Having three or more risk factors increases the risk for later CW. Language was the most consistent predictor of group membership, but the depth of cognitive risks beyond language was associated with the severity of reading impairment. However, neither the breadth nor the depth of risks could adequately predict individual outcomes. These findings align with a multiple risk view of reading CW and highlight the challenges in early identification. SUMMARY: Children with comprehension weaknesses (CW) in mid-childhood had language weaknesses at 24 and 38 months, but prediction was poor at an individual child level. The breadth of early risk factors related to both the presence and severity of later CW, but remained poor predictors of individual outcomes. While lower levels of preschool language were a risk factor for poor comprehension, other cognitive factors were associated with the severity of difficulties. These findings highlight the challenge in identifying children at risk for comprehension difficulties, and emphasise the need to look both at language and beyond language.