Recent research by Purdue University on retrieval practice finds that test-taking is, by far, a more effective learning activity than either studying or concept mapping. The findings were published by Science Magazine, then reported on by the New York Times.
Reflecting back on my days of formal learning, I can say my personal experience supports these findings. My retention of knowledge was far greater after having taken the tests that were intended to simply assess that learning. They generally were the most powerful learning tools in the curriculum.
The synthesis and application of knowledge and skills that is needed to successfully complete a test cements the learning deeper and in a more tangible, useful fashion. Additionally, I am wondering whether the meta-skills needed for test-taking are those skills needed to apply learning in practice.