"In the last decade, U.S. colleges graduated three times more scientists and engineers than the number of jobs available, the researchers said. The data went through 2005 and did not reflect the recession."
It sounds like this research was "Hey department of education how many science or engineering graduates are there in the US every year?" and "Hey bls.gov how many openings are there that match engineer or scientist for entry level positions each year?" Now divide and we are done. Conclusion, there are way to many people with science and engineering degrees.
This is drawing conclusions about the labor market with a data set that includes a wide range of degrees many of which are only prerequisites for graduate degrees in other fields.
I agree, But what if we looked at a job where productivity should be much easier to define, like a roofer.
An obvious performance metric would be "Time it takes to install a roof that will pass a quality inspection". That metric is pretty useless alone though. Can he fix a nail gun that breaks? How safe is he? Can he work as fast in cold weather? are just a few factors.
Say you could get metrics for ALL productivity factors, you still haven't taken into account personality issues that cannot be quantified.
And this is for a single person working on a measurable task with only a few tools. What chance is there for metrics to be accurate about a task that could require any number of tools, multiple correct answers, and collaboration?
That is why a lot of people look at the payroll report at the same time. But the payroll report usually comes with large revisions.