What do you do when a child bombs a test?

 ob and I have two different approaches to tests.  He mainly teaches Math and Physics.  Rob grades the test and then allows half-credit for corrections.  I make kids edit their Biology tests, which are largely essay tests.  However, some tests in Chemistry, like Algebra, are skill-based.  If a teen blows the test, he or she retakes the test.  In the Algebra I class, Rob is doing both this time.  If the kid misses one or two questions, he or she gets half-credit for corrections.  If the kid really bombs, Rob or I review the original test with the teen, line by line.  Then we give the child a new test to take for full credit.  What is interesting is that most of the class thinks this approach is fair.  Everyone knows he or she could bomb a test, too.  None of the kids want to retake a test.  Essentially, there is a safety net.  However, this approach emphasizes understanding over raw achievement.