Oh how I hate the word genius.

We use it as a shorthand to mean “super smart.” But it lacks any objective definition. We can point to athletes and say “she ran faster than anyone,” or “he jumped higher than anyone” or “that team scored more points than anyone.” But when it comes to intelligence, we struggle to define it. You can be smart at one thing and dumb at many more things. Does that make you a genius?

Take Elon Musk. His efforts at Tesla and Space X make me think it’s fair to call him “smart” or “bright” or “intelligent” or “genius.” Sure. Even if I wanted to argue that his genius is overrated, it’s not like I can point to objective metrics to make my point. It just comes down to a subjective gut feeling, like calling someone “hot” or “funny.”

But there are objective metrics for product design, and he’s one of the dumbest business leaders we’ve ever witnessed, in the history of the world. Pull up chair. This is my specialty and I have receipts.

If a product has one million users before you take over, then two million users a year later, you can reasonably say you doubled the success of the product in the marketplace. And if you look at your peers and their growth is averaging 5% to your 100%, you can reasonably argue that you’re a lot better. And if you wanted to throw the word “genius” around, sure, you could say you’re a branding genius, or a marketing genius, or a product genius, or a business genius. Then people could look at the numbers and agree or disagree. But always through the lens of numbers and metrics.

So, using numbers as metrics, Elon Musk isn’t just “not a business genius,” he’s an abject failure. If you think that’s just a squishy opinion, I’ll direct you to the metrics. He bought a company for 44 billion that is now worth, by his own admission, less than half of that. His number of users is lower. His number of advertisers is lower. His income is lower. I don’t know what his customer satisfaction numbers are, but Gallup is reporting that only 40% of Twitter users are sure they’ll be using the service in a year. 35% are “somewhat likely” to use it, and 25% say not at all. (The number jumps to 35% when you ask women)

Elon Musk might be a science genius, and his marketing and branding eye seemed to have worked very well at Tesla. I’m comfortable calling him a genius there, because I can point to the numbers that prove his savvy and acumen compared to his peers. But he’s definitely not a social media, product design, or strategy genius. Nothing in his performance at Twitter could reasonably support that argument. Instead, Musk defenders are forced to explain why destroying a 44 billion dollar company can be called anything but a failure.

Imagine an experiment that could simulate how 100 random Americans handled being Twitter’s CEO. I believe Musk would be outperformed by every single one. A large percentage of them would be terrified by the responsibility, so they probably wouldn’t change much. They’d probably lean heavily on their leadership team, and when faced with unified resistance to their ideas, they’d probably back down from them. Another percentage would be more confident, but again, there would be a limit to how much they’d attempt to change at once. No matter how much you hate Twitter, you probably wouldn’t actively chase advertisers off the system, for example. But Musk did.

No one would be as bad at Musk. Blue collar workers, 16 year olds, old ladies who would rather be knitting and watching Matlock, consultants, other CEOs, no one could mess up as badly as he has done. And yet we call him a genius.

I’m not saying he’s stupid, necessarily. But I genuinely believe one hundred monkeys at typewriters would have done a better job running Twitter. So where does that leave us? Is he still a genius at some things? Sure. But he’s also – objectively – the biggest loser in the history of CEOs. Both can be true at once, in the same person. But only one of those assertions is based on objective data. And it happens to be the one that matters.