Always give students time to revise their work after assessing themselves, then have them assess one another's work. Peer-assessment takes some getting used to. You may also need to hold students accountable for their assessments of a classmate's work by having them sign off on the rubric they use. You can then see how fair and accurate their feedback is, and you can ask for evidence that supports their opinions when their assess-ments don't match yours. Again, giving time for revision after peer-assessment is crucial.
Parents can use rubrics to help their children with their homework.
When you hand the marked rubric back with the students' work, they'll know what they did well and what they need to work on in the future. A piece of work that reflects the highest level of quality for each criterion obviously deserves an A, one that consistently falls in the lowest level is a D or F, and so on. Because one piece of work rarely falls in only one level of quality, many teachers average out the levels of quality, either formally or informally. Rubrics can also be included in portfolios. However you use them, the idea is to support and to evaluate student learning.