Not nearly enough

From Does Reading During the Summer Build Reading Skills? Evidence from a Randomized Experiment in 463 Classrooms by Jonathan Guryan, James S. Kim, and David M. Quinn

The abstract:

There are large gaps in reading skills by family income among school-aged children in the United States. Correlational evidence suggests that reading skills are strongly related to the amount of reading students do outside of school. Experimental evidence testing whether this relationship is causal is lacking. We report the results from a randomized evaluation of a summer reading program called Project READS, which induces students to read more during the summer by mailing ten books to them, one per week. Simple intent-to-treat estimates show that the program increased reading during the summer, and show significant effects on reading comprehension test scores in the fall for third grade girls but not for third grade boys or second graders of either gender. Analyses that take advantage of within-classroom random assignment and cross-classroom variation in treatment effects show evidence that reading more books generates increases in reading comprehension skills, particularly when students read carefully enough to be able to answer basic questions about the books they read, and particularly for girls.

I don't have access to the paper but Fivethirtyeight has an account.

Taken together, the results of this study suggest that the answer to the question posed by the title is not a simple ‘yes’ or ‘no.’ Going through the motions of reading without being focused enough to remember basic facts about the book may not be effective at building lasting reading skills. Reading carefully and with enough focus to be able to answer reading comprehension questions about the book appears to build reading skills that improve comprehension of other texts weeks or months later. How best to get children learning to read in an engaged and focused way remains an open question, and would be a promising area for future research.

There it is again, the issue of sustained focus as a driver of desired outcomes. So often we focus on inputs as a measure of outputs instead of simply measuring outputs.

What you most want to understand is what are the necessary inputs, what are the necessary causations in the process and what are the associated outcomes. Too often, in the public policy arena, we ignore causations, fail to measure outcomes and focus strictly on inputs. How many books was the child exposed? As this research indicates, that doesn't really tell you much. What you really want to know, is with how many books was the child cognitively engaged? That is a lot harder to measure but much more predictive of the desired outcome, i.e. an enthusiastic and effective reader.

How many schools are good at creating the behavior of sustained and engaged reading. Not nearly enough I think is the easy answer.