Critic John Simon’s Critical Measure:

“If you like eight out of 10 shows that you review, you should be in a different business,” he said. If you like six to eight, you might be aware enough to write “puff pieces” about shows. If you like five out of 10, “then you don’t exist. You’re too perfect.” If you like two to four of those 10 shows, you might be able to be a reviewer, and if you like zero to two, “you may be a critic, but there’s no guarantee.”