Are vocabulary and word reading reciprocally related?

Purpose: The purpose of this study was to examine if word reading and vocabulary are reciprocally related. Method: We followed a sample of 172 English-speaking Canadian children (82 girls, 90 boys; M_age  = 75.87 months at the first measurement point) from the beginning of Grade 1 until the beginning of Grade 3 and assessed them three times on vocabulary and word reading. Results: Results of cross-lagged analyses revealed only unidirectional relations: word reading in Grade 1 predicted vocabulary in Grades 2 and 3. Conclusion: These findings suggest that once children reach a basic level of proficiency in word reading this allows them to be independent readers and enhance their vocabulary.