I have not read the book, nor looked at the spreadsheets. But as someone who knows a bit about argumentation, I have to point out that, often, if you are forced to argue about the specific data, you have already lost the argument. Data (and quantitative arguments) are appealing because they appear to be "un-biased", but the person picking the numbers has already set the terms of the debate. Someone else might point out that a set of numbers measure some things accurately, but not everything. One might point out that averages (perhaps, on average, many college students learn little more than they learned in high school) obscure the extremes (for some groups, particularly poor people with poorly educated parents, high school and college are far more efficient paths for improving quality of life than any alternative).
It sounds good to say that you can't argue with the data, but you can certainly argue with how the data was picked.
It sounds good to say that you can't argue with the data, but you can certainly argue with how the data was picked.