If you believe that widely unequal schools are responsible for achievement gaps, open my book to page 17 and look at Figure 2.1. That figure shows that high-SES children are ahead of low-SES children in reading skills by .64 standard deviations at kindergarten entry. At this age, we are really measuring mostly pre-reading skills, like knowing letters and the sounds they make, and recognizing a few simple words and short sentences. The standard deviation is a useful way to gauge the gap between two groups because it allows us to assess the magnitude of that gap, even when the kinds of reading skills assessed are different at later ages. If schools increase inequality, we should observe a growing gap (as measured by standard deviations) over time. Over the next nine years, however, this gap does not increase in the way it should if schools are the culprit. Instead, it declines to .55 standard deviations by the end of the eighth grade. The math results, Figure 2.3 on p. 19 in the book, show the same pattern.If these patterns were unique to the ECLS-K:1998 data, we might be able to dismiss them, but the overall pattern replicates in a wide range of nationally representative datasets. It is really hard to develop a story about schools that is both consistent with this pattern and defines them as a source of achievement gaps. Instead, the patterns suggest that children arrive at kindergarten on highly unequal learning trajectories. Once in school, however, achievement gaps largely stop growing and even begin to narrow somewhat—the very opposite of what we would observe if schools were a source of achievement gaps.My hope is that this book prompts a more careful consideration of schools’ role in shaping achievement gaps. The assumption that schools are largely responsible is misplaced and can divert attention from larger social problems that likely are the source.Consider how we stack up against Canada. Our 15-year-olds score .30 standard deviation units behind Canada’s on international reading tests. Most would blame our schools for this gap but it turns out that the same cohort of children were .31 standard deviation units behind Canadians at age 4-5, before schools had a chance to matter. This pattern highlights how school reform is not the likely explanation for why our teenagers’ skills are behind those in other countries. The problem is rooted in early childhood conditions where too many of our children experience stressful environments. Notably, high-performing American five-year-olds did about as well as high-performing Canadian children. The large gap across the two countries is due primarily to very poor-performing children. The U.S. has more very poor-performing students than does Canada.So, are Canadian children just genetically superior to American children? That doesn’t seem likely (unless you’re Canadian). A more plausible explanation is that Canadian children, on average, experience better early childhood conditions. And that is likely due to a broad range of policy decisions Canadians have made differently than Americans, such as the provision of universal health care, which reduces stress for the disadvantaged. Of course, the battle in the U.S. over policies like universal health care is a more difficult battle than school reform. But just because it is easier to focus on schools does not mean that they are the appropriate policy lever. Reducing inequality requires us to think bigger than school reform.