Mark Schneider nailed one problem posed for No Child Left Behind (NCLB) by the new math results—the gains in math prior to NCLB were larger than they have been since. There’s another problem Mark didn’t take up: No progress in achieving the most highly touted objective of NCLB, closing the gap in black and white test scores. From 2004 to 2008, the difference in scores went up by a trivial 2 points for 9-year-olds, down 2 points for 13-year-olds, and was unchanged for 17-year-olds.
To examine trends over a longer period of time, the National Center for Education Statistics has implemented an easy and flexible online tool, the NAEP Data Explorer, that makes it easy to ask whatever questions you wish. I created tables with the scores and standard deviations for blacks and whites, then calculated the black-white gap in terms of standard deviations. (For people who aren’t familiar with standard deviations but are familiar with the SAT math test, a standard deviation is around 115 SAT points.) Here’s what the plot looks like:
The NCES changed the assessment format in 2004, reporting scores for both the old and new version, hence the funny discontinuities in the graph at 2004. But the overall story is pretty simple. In the early years, the gap narrowed, most impressively for 17-year-olds. For students ages 9 and 13, not much has changed since then. The narrowest gap for 9-year-olds was reached in 1986 and has moved within a narrow range since then. The narrowest gap for 13-year-olds also occurred in 1986, followed by a rise through the 1990s, then a decline in the 2000s to about where it was in 1986. The narrowest gap for 17-year-olds occurred in 1990, followed by a widening. It is not an encouraging picture.
Now suppose you approach the data differently. Instead of looking at the trend by the year the test was administered, look at it according to the year the children were born. This means that we have multiple sets of scores for some years. For example, children born in 1971 are represented at all three ages (9, 13, and 17) through the National Assessment of Educational Progress (NAEP) tests administered in 1980, 1984, and 1988. If you average the black-white difference across age groups, this is what you get:
The narrowing of the black-white gap extends from children born in 1961 through children born in 1973, and it was substantial—from 1.2 standard deviations to about .8. Then the trend goes flat, with a few spikes, for children born over the next 26 years.
You can’t use this graph as proof of anything for a variety of technical reasons (the systematic differences in scores for different age groups have to be taken into account). I present it because it is consistent with many other datasets, analyzed in more sophisticated ways.
A few years ago, my colleagues (and friends) Bill Dickens and Jim Flynn published a widely publicized paper arguing that the standardizations of the major IQ tests show that the black-white IQ gap dropped by 4 to 7 IQ points between 1972 and 2002. Those years refer to the years that the tests were administered. As far as I can tell, their findings are almost completely consistent with my alternative proposition, to wit: the black-white gap in cognitive test scores narrowed for people born from the first decades of the 20th century into the early 1970s, and has not dropped for people born thereafter.
The timing of the narrowing is hard to pin down, but the greatest portion of it might well be concentrated among people born in the 1920s, 1930s, and 1940s. The evidence that the narrowing stopped for children born since the mid-1970s is much more detailed—from the NAEP, the SAT, the standardizations of the Wechsler adult IQ test and of the Stanford-Binet IQ test, and, most powerfully, the extensive testing of the thousands of children born to women of the 1979 cohort of the National Longitudinal Survey of Youth.
There was also narrowing between the 1979 and 1997 cohorts of the National Longitudinal Survey of Youth, but all we know is that it occurred among people born sometime between 1964 and 1980—we don’t know what birth years account for the narrowing. The only data that directly contradict my proposition (that I’m aware of) come from the standardizations of the Wechsler IQ test for children. The latest results from the NAEP are one more bit of grist for my side of the argument.
So I solicit evidence that the black-white gap in test scores has narrowed for people born since the mid-1970s, and suggest that, if the balance of the data continues to point in the other direction, it behooves social scientists to explore why the narrowing was so substantial before then and so flat thereafter.