I believe it is important for students to reflect on their work and to learn from their mistakes. So many times, I have had students who fly through assessments because they 1) feel confident and don't need to work carefully, or 2) just aren't really focused on their work. This error analysis has been a powerful way for students to review their work on unit tests after they have been corrected, to find their mistakes, and to explain those mistakes clearly. All of these exercises have proven to be helpful to my kids in terms of preventing similar mistakes in the future or noticing general patterns in their individual approach to test-taking that bring their scores down.
I have them write the number of the question they got wrong on the first line in the first box, then carefully re-solve the problem in the empty space in that box. In the box below it, I have them explain in words what mistake they made. I have found that if they can clearly articulate the mistake that they made, they are less likely to make the same mistake later. If they got multiple problems incorrect, they may use the other boxes on the page in the same way.
The second page is for open response questions and can be used or ignored as desired. If the test includes an open response question, this page should be used in the same way as the other tests questions; it simply provides more space because of the amount of visuals/explanations they might need to thoroughly answer it.
At the top, you may alter the heading to reflect whichever unit test on which you are currently having them analyze. If students get more than 4 questions on the test incorrect, you may simply copy the first page twice.
As an added bonus, I usually allow students who have found their mistake, answered the question correctly on their error analysis page, and thoroughly explained their original mistake to earn a few points back on their test. For example, if question 1 is worth 10 points, and they are able to complete the error analysis for this question meeting all the above criteria, I might add 2 points back to their total test score. For some kids, this aspect of the error analysis has been highly motivating and a way for them to boost their grade while simultaneously learning from their mistakes. This can be done at the teacher's discretion, of course.
I think this could be used at almost any grade level, but have tagged it as useful for students in grade 4 and above. Certainly, younger students might be capable of this reflection as well, but the wording/format of the sheet might need to be altered to their levels.
I hope this is helpful!