A recent study finds 8th grade math and science students perform better on tests when their teachers spend more class time lecturing rather than providing group-work or other problem-solving activities. More details about the article and study can be found here.
Well, this is not a shock. Factual material (and in particular, foundational material) is best presented through a lecture, especially with the content that's currently taught in middle-school math and science. Additionally, these students weren't asked to apply the concepts they were taught, i.e. the research was completely based on the results of a standardized test.
I guess this is breaking news to some people: if you desperately want students to pass a test, teach to the test. In other shocking news, hard-working teachers aren't paid enough.