First off, high school graduation rates have been steadily improving for the last 30 years, consistent with the push to improve school performance. The following table shows the national average dropout and graduation rates (all ethnicity combined) from 1980 to 2008. The dropout rate was nearly cut in half. One would assume then that the students must know more on average, since more of them are graduating.
|National Dropout/Graduation Rates by Year - from NCES|
Looking at standardized test scores however, we see that they don’t. The same math test was given to 9, 13, and 17 year-olds from 1973 to 2008. The scale range was 0 to 500. The 9 and 13 year old show noticeable improvement in those years, however the 17 year olds haven't changed. Apparently the primary schools are doing something right that the secondary schools are lacking.
|Standardized Test Scores|
Finally, there is some data available at the college level showing the high school grades of incoming freshmen. High school GPA can be correlated to remedial classes taken by the students in college for two time periods, 1995 and 2004. Sure enough, the percentage of straight A students needing remedial coursework in college more than doubled in that time period, while the overall percentage went up only slightly. This is particularly troubling if you consider that colleges are also experiencing grade inflation, so the bar on what would necessitate remedial coursework is no doubt lower today than in the past.
|Remedial College Courses|
So there you have it. Yes, graduation rates are improving, but no, education in America is not better off for it.