From EduTopia:

This blog post looks at how assessment focused on a partnership between students and educators may be more effective than traditional top-down approaches by teachers who decide where students are on a continuum of learning. The author, Bob Lenz, is the founder of Envision Schools in San Francisco, where students are engaged in directly assessing their own progress. Lenz argues that students who assess themselves are learning and improving their cognitive skills while assessment is happening and that when students assess their own work by identifying strengths and weaknesses, the likelihood that they will do better next time is greater.