What is the primary factor that contributes to children's comprehension of written text upon entering school?

The primary factor that significantly contributes to children's comprehension of written text when they enter school is explicit instruction in language development. This instruction provides children with the foundational skills they need to understand and process language more effectively.

Language development includes vocabulary expansion, understanding sentence structure, and grasping the nuances of language, which are all essential for reading comprehension. When children receive clear, structured teaching that focuses on these aspects, it helps them not only decode words but also interpret the meanings behind them. This foundation is vital for making sense of the text, connecting ideas, and engaging with more complex materials as they progress through their education.

Other options, while beneficial, do not have the same level of direct impact on comprehension as explicit instruction. Rigorous texts may challenge students but could also lead to confusion if they lack the necessary foundational skills. Engagement with leveled readers is useful for practice but may not alone provide the deeper understanding that comes from direct instruction. Likewise, the use of visual aids can support comprehension but is typically most effective when combined with strong language development skills. Thus, it is the explicit instruction in language development that plays a crucial role in shaping a child's ability to comprehend written text upon entering school.