Number of books in the home

I am always looking for data that sheds some light on the real outlines of reading: how much do people read, how often, where, what types of reading material, how much do they spend, etc.

One long standing question is how many books are present in the average home. From Falling Behind: New evidence on the black-white achievement gap by Roland G. Fryer and Steven D. Levitt. They are looking at reading from the perspective of race achievement gaps but they do have this nugget, referencing data from the Early Childhood Longitudinal Study.

The number of books in the household is a useful proxy for the home environment’s contribution to academic success. Adjusting the test-score data for this factor reduces the gap even more. On average, black students in the sample had 39 children’s books in their home, compared with an average of 93 books among white students. Taking this difference into account cuts the black-white test-score gap to less than a fourth of a standard deviation in math and completely eliminates the gap in reading. The gap between white and Hispanic students also shrinks.

In another report, Non-cognitive Skills and the Gender Disparities in Test Scores and Teacher Assessments: Evidence from Primary School by Christopher M. Cornwell, David B. Mustard, and Jessica Van Parys, also using Early Childhood Longitudinal Study data, they indicate:

# Books in the home
Kindergarten - 81.7
First Grade - 112.36
Second Grade - 135.98
Third Grade - 117.91

but with very large standard deviations. They don't specify, in a fashion that I can identify, whether these are total books or children's books.

In another report by Fryer and Levitt, The Black-White Test Score Gap Through Third Grade, they indicate

Number of Children's Books in the Home

Total, White, Black, Hispanic, Asian
Kindergarten 61.4, 81.4, 32.3, 35.8, 33.8
First Grade 74.6, 102.5, 31.6, 38.8, 40.1
Third Grade 76.8, 103.8, 33.3, 44.9, 43.4

So in total, since this data is all sourced from the same longitudinal study, it is a little confusing as to what the actual numbers are. My basic take-away is that the average home has somewhere between 60 and 120 children's books but that there is substantial variation based on race (and I would suspect even more variation based on class/income). So no solid answers but at least indicative.