What do the record high school graduation rates mean? Simply that more kids are staying in high school for four years. When unemployment especially youth unemployment is at record levels, what other options does a teenager have? Lack of jobs is also a major factor pushing up college enrollment. It's a way to postpone job hunting until the economy improves and perhaps improving one's prospects with a degree.
Higher graduation rates do not, unfortunately translate into a better educated workforce. Sitting in a classroom is not necessarily the same as getting an education. Yes, students take standardized tests in English and math early on in high school but they are not required to pass them to "graduate". They can graduate with a "waiver" and receive a diploma for sticking it out for four years. Or as Wendy put it a few years ago, "the tests are not an issue" keeping kids from graduating. In other words, any kid who doesn't drop out is guaranteed a diploma. The typical 50% remediation rate for college freshmen show what has happened to the value of that diploma.
All other things being equal, the higher graduation rates would be a good sign. But we'll have to see what happens when the economy recovers to see if the trend is real.