The Impact of Word Reading and Vocabulary on Middle School Reading Comprehension

 Hello Literacy Friends!

As I continued to update my knowledge for my upcoming Literacy Difficulties course, I came across a very recent article that examines the relative impact of word reading and vocabulary knowledge on the reading comprehension of adequate and struggling adolescent readers. I found that the article does an excellent job laying out these relationships and thus gives real insight into the causes of differences in reading comprehension among adolescents. I will try to unpack the findings in an efficient manner for you all here.

First, the study included 796 middle schoolers (average age of 14.1), with 491 in the adequate comprehension group and 305 in the struggling comprehension group (below 30% on the Gates comprehension test). These students were assessed for vocabulary knowledge, word reading, reading efficiency (fluency), and inferencing. The researchers analyzed the direct and indirect effect of word reading and vocab knowledge on reading comprehension. (Indirect effects included the effect of each these two components on reading efficiency and inferencing multiplied by the respective effect of reading efficiency and inferencing on reading comprehension.) In the end, the authors could then consider the total effects of word reading and vocab on reading comp for a) the total sample, b) the adequate comprehenders, and c) the struggling comprehenders. So, here, in a nutshell, are the outcomes:

1)    Word reading was a significant predictor of comprehension for the entire sample (effect .21); however, word reading had a large effect on comprehension for struggling comprehenders and a negligible effect for adequate comprehenders. This supports the notion that, in the authors’ words, “there is a threshold of word reading skill that has to be met before its relation to reading comprehension subsides. It is possible that the struggling comprehenders did not have the requisite word reading skills necessary to easily extract meaning from text.”

2)    Vocabulary was a greater significant predictor of comprehension for the entire sample than word reading (effect .60). Vocabulary had a larger effect on comprehension for adequate comprehenders (.62) than struggling comprehenders (.18). The authors summed up these results in this way, “While vocabulary favored the adequate group as a predictor, it was also a statistically significant predictor for the struggling comprehenders. Thus, vocabulary plays an important role for struggling and adequate readers alike.”

3)    Vocabulary knowledge significantly positively impacted the adequate readers’ reading efficiency and inferencing. In simple terms, students with higher vocabulary scores were slightly more fluent readers and better at making inferences.

4)    Without getting into the more complex details, the outcomes related to the struggling comprehenders led the authors to conclude… “instruction in word reading and vocabulary may lead to greater gains for struggling readers than instruction aimed at increasing fluency. Indeed, this view is supported in the synthesis of effective interventions for struggling adolescent readers by Edmonds et al., who found that word reading instruction led to greater and more consistent gains than fluency instruction.”

I would summarize things this way. It is clear that word reading difficulties have a strong impact on students’ comprehension. Basically, until students can read the words well, other components matter less: the students are simply hung up on reading the words. On the other hand, once students reach a high level of word reading proficiency, knowing the meanings of the individual words greatly impacts their reading comprehension, both directly and because it makes them better at inferencing and slightly more fluent. 

My takeaway is that elementary schools should prioritize both of these key components! I believe that it quite feasible for elementary schools to equip nearly all students with strong word reading skills, and, if we can, we should. But, just as significantly, vocabulary knowledge was a significant predictor of comprehension for all students and particularly for the adequate comprehenders. Teachers often ask me, “We rightfully think a lot about our lower-performing students. But, how can we push those kids right in the middle to a higher level? Well, this study shows that if we want students to be especially strong comprehenders in middle school, we need to be teaching vocabulary comprehensively and consistently across the elementary grades. So, at this point, I’ll put in a plug for my earlier CLC post on VALE vocabulary instruction. Check it out below! 

Oslund, E., Clemens, N., Simmons, D.. & Simmons, D. (2018). The direct and indirect effects of word reading and vocabulary on adolescents’ reading comprehension: Comparing struggling and adequate comprehenders. Reading and Writing, 31, 355-379.