Last time, I wrote that having books in the home seems to boost kids' scores on national tests by a significant amount. Today I report on an international study showing that having more books in the home appears to increase the number of years of schooling a child attains.
Some of you have already read about this study, but when a study takes twenty years to complete, it doesn't become old news that fast.
Basically, M.D.R. Evans and colleagues found that across countries and cultures (e.g. black vs. white South Africans), having 500 or more books (rather than only one book) in the parental library translated to an average of 3.2 more years of schooling attained. The impact was greater in poor countries than rich countries, with the highest effect in China (6.6 years) and the lowest effect in Canada (1.6 years). These differences were as great or greater than the difference between having parents with 15 years of schooling versus parents with only three years of schooling.
In the US, the effect of having 500 versus one book was 2.4 years of schooling, after controlling for other measures of family background, such as parental education, income, or occupational status. Across the 27 countries, the steepest part of the curve was toward the end with fewer books; that is, the first 25 to 75 books are just as important as the next 400+. As the authors say, "It is at the bottom, where books are rare, that each additional book matters most, not among the literate elite; each additional book yields more 'bang for your book' among the book-poor than among the book-rich."
Of course, it's not just piling books in a corner somewhere that makes the difference. Households with books tend to be households where parents nurture a scholarly culture by talking about ideas, encouraging reading, and sharing knowledge. Parents at any level of wealth or education can encourage such a culture, and books are a great resource to help it happen. So are public libraries.
Two final notes of interest. The first is that the average number of books in American homes is 112, about average for the 27 countries studied; but based on wealth and education levels, we would be expected to have more like 200 books per household. So maybe we're shortchanging our kids.
Second, although number of books in the home has proved to be a valid indicator of scholarly culture in the past, correlating well with other measures like how often parents read about science or go to the library, that may change as more of us turn to using ebooks instead.