The most useful product of test scores is that they give us a way to compare students. So while few people want to learn exactly the same thing as the person sitting next to them, we force students to learn the same thing as the person sitting next to them anyway, so we can test them on the same material and compare the results. If you want to rank children or if you want to rank schools or teachers, test scores are very useful. The question is, “Why do we need to rank students?”

1. Test scores help predict linear outcomes.
If we were all aiming for the same thing, then we could all learn the same thing and predict how quickly and effectively we would get to what we're all aiming for. Test scores would be that predictor. But kids aren't like that. Kids aim for an unlimited range of goals and they change an unlimited amount of times throughout their life.

Test scores are predictors of a linear progression, but there is nobody advancing in a linear way. Which means when you finish teaching the kids the test, they go out into a world where test scores don't matter. At best, this means that you’re giving kids a useless skill. At worst, this means that you're going to send your child into a world where they're completely unprepared for the non-linear life of adulthood.

2. Test-taking strokes parents' egos.
Most of us grew up in a world where we got rewarded for what we did in school and then we get rewarded for what we do at work. For example, you get a raise or a promotion. But in parenting, there are no rewards beyond the love you give and the love you get. So lots of parents use the scores from test-taking to give themselves a little reward. “My kid is smart. My kid is a hard-worker. My kid is better than your kid, therefore I am good.”

This is especially true of homeschool parents, because sending kids to school wastes about 80% of the kids’ day, which means that with very little effort, a homeschool parent can get their kid testing two or three grades ahead of their grade in public school. But if your kid is really a genius, the worst thing you can do is give them a set curriculum and a test to measure that. Brilliant kids are amazing critical thinkers and should be looking at questions with no clear answer.

Here's an example of a kid who created a simple test that changed how cancer and other fatal diseases are diagnosed and treated, and here's his parents' philosophy on how to raise a brilliant child. Note: There is no test-taking here.

3. Test scores provide credentials.
In the old world, there were specific hoops you jumped through to have a good life. Get good grades, go to college. Go to college, then get into law school. Get a good internship, become partner. Or here's another one: Get good grades, go to college, get a job at Proctor & Gamble, work there fifty years, and get a gold watch. Those are two paths through life that are no longer open to people. We don't stay at a job for fifty years.  And almost nobody makes partner. (In fact, most law school students are unemployed.)

This throws into question the whole idea of credentials. Credentials get you into the world of other similarly-credentialed people. The world of work and education is changing much too fast for credentials to keep up. Stanford and MIT are teaching courses to people who can't get into the schools and companies are actively recruiting people with no college degree and venture capitalists are paying kids to forego formerly non-negotiable credentials like college education.

Really, the most interesting part of the education revolution today is the world of badges. So you can be a graduate of Kahn University. You can graduate from Marginal Revolution University. And Rheingold U.

To give you a sense of how important badges are to the next generation, let's talk about Reddit. This site  is pretty much the starting point of all viral news online, and it started issuing badges to show how long you've been in the Reddit community. My friend Melissa has been reading Reddit since it started six years ago, and she's incensed that she didn't sign up the proper way, so her badge on Reddit shows only two years. Even though nothing in Melissa's life shows that she's fluent in Chinese or was on the Oprah show as a child, this isn't what she cares most about. But she definitely cares that her badge doesn't properly acknowledge her intellectual contribution online.

We talk a lot about the cost of test-taking. People want to get rid of No Child Left Behind because it's so test-based. The protest movement to opt-out of tests runs from coast to coast. And private schools are foregoing the majority of tests that public school kids have to sit through.

But next time you're nervous about your test scores, instead of worrying about the cost of the test and what it's doing to your child, you can also consider the benefits, and how paltry they are in the new world order, where education and work require a much more expansive type of knowledge than any test measures.