Predicting Literacy Skills at 8 Years From Preschool Language Trajectories: A Population-Based Cohort Study.

Purpose: This article explored the predictive values of three main language delay (LD) trajectories (i.e., persistent, late onset, and transient) across 3-5 years on poor literacy at 8 years. Additionally, the effect of gender was assessed, using both gender-neutral and gender-specific thresholds. Method: The data comprised mother-reported questionnaire data for 8,371 children in the Norwegian Mother, Father, and Child Cohort Study. Analyses were conducted using binary logistic regression in SPSS to make predictions about risk. Results: LD reported at preschool age was associated with excess risk of poor literacy at 8 years with odds ratios ranging from 3.19 to 9.75 dependent on trajectory, persistent LD being the strongest predictor. The odds ratio of transient LD was similar to that of late-onset LD. Gender was not found to play an important role in the association between oral language and literacy, as the gender difference disappeared when gender-specific deficit criterion was used. Conclusion: Our study supports the longitudinal association between preschool oral language and school-aged literacy skills and highlights the importance of different LD trajectories across preschool ages in predicting later literacy. Furthermore, practitioners are recommended to consider gender-specific cutoffs in relation to language and literacy measures.