It is virtually impossible to think about schools without thinking about grades and test scores. For many, they are taken for granted as the way to judge results. Test scores have many advantages. They feel reassuringly final: no wishy-washy changing them after the fact. They seem scientifically precise: if you want to know if students are learning, just compare one number to the next. They are gratifyingly simple: no worrying about the confusion of whether a student is a 95 in one area but a 65 in another, with a grade you can average it all out to one clear 80. And they carry the weight of tradition: chances are they were definitional to your own high school experience.

But ubiquity does not necessarily translate into effectiveness.

Imagine what it would be like to be graded, today, on everything you do. Yes, most well-run businesses have some form of performance evaluation, but in almost none are they as drearily stark or as highly relied upon as in public schools.

If your boss is effective, they probably don’t average everything about you into one simple number. Instead, you receive feedback on a number of different areas: “Overall you’re doing pretty well, but you still need to work on how you manage projects.” Most likely, you know that you are better than your colleagues in some of those areas and worse in others. Yet most report cards ask teachers to boil all of their feedback down to the gratifyingly simple (and frustratingly one-dimensional) overall average.

If your boss is effective, you probably expect them to give you a broad sense of how you’re doing and how you’re improving: “The meeting you led yesterday wasn’t so effective, but during today’s I saw people really engaging.” But you’d smirk if they tried to translate everything into an exact number. “The meeting you led today was an 85, but yesterday’s was just a little worse: an 83. Nice improvement!” Yet in schools, we act as if teachers and tests can carefully track and record progress with precision that no boss could ever muster. Indeed, entire programs and systems get multimillion-dollar grants based on the claim that students are increasing a certain number of points on tests.

If your boss is effective, you probably expect them to engage you in a conversation about your performance and think with you about how to improve. Yet the way most report cards are set up, they bring with them the finality of an indelible mark on a student’s transcript; reassuring, perhaps, for adults who want to judge students, but not for students themselves.

In short, only a really ineffective boss would give grades the way we expect teachers to in many schools. Any time I look at statistics on student growth or teacher effectiveness measured against student grades and test scores, I try to remember this. We need to figure out how to make more effective schools. But we will never manage to do that if we are relying on grading systems that force our teachers to be bad bosses.