For most of my career, I carried a number. If you've ever led sales, you know exactly what I mean, because the number is the first thing anybody asks you about, and a lot of the time it's the only thing. As Chief Sales Officer, I doubled our company's revenue in two years, and then I was let go anyway. So yes, I've done a whole lot of thinking about what a number can tell you about a person and what it can't, and a while back I came across some Harvard research that gave me a brand new way to talk about it.

The reason had nothing to do with my results. The CEO had stepped back into the business, and the leaders closest to him were people who had grown up under him, people he'd known for years. I came from the outside; the person who hired me was let go, and one by one, so was everybody that person had hired. I thought differently; I spoke up, I said what I believed was right for the business, and I didn't fit the mold of a yes person. What gets me now is how much I'd hidden to try to fit. I kept huge parts of myself out of that office, my beliefs, my intuitive gifts, who I really was, because I was sure that if he knew, he'd let me go. He never knew any of it, and he let me go anyway. All that masking didn't protect me; it just meant I spent those years being less of myself for nothing.

Dylan Minor at Harvard Business School teamed up with a data scientist named Michael Housman, and together they dug into anonymized data on almost 60,000 front-line workers, folks in sales and tech support and customer service across 11 companies. Everybody else in the talent world was busy asking how to find more superstars, and these two asked the opposite question, which was what it actually costs you to hire the wrong person. And they didn't mean the person who misses quota. They meant the person whose behavior gets bad enough that they get fired, things like bullying, harassment, and fudging the records.

So what did they find? Steering clear of one toxic worker saved a company about $12,489, while landing a true superstar, somebody in the top 1 percent, added about $5,303. Read those two again, because the toxic hire costs more than twice what the superstar brings in, and Minor thought even that was lowballing it, since it doesn't count lawsuits.

(If your leaders could use this conversation, it's part of my keynote, Switch On Your Light, and you can find it at karabundedunn.com/speaker.)

Now, these toxic workers weren't slackers. On average, they were really productive, which means that if you hire and reward people on output alone, you'll end up with more of them, not fewer. And it doesn't stay contained, either, because the people working next to a toxic colleague got more likely to turn toxic themselves over time. It's catching.

One of the biggest red flags in the data was overconfidence: people who rated their own skills way higher than they could actually perform when they were tested. I'll be honest, that one hit close to home, because so much of corporate life trains us to perform certainty. We learn to sound sure in the meeting even when we're not, and then we turn around and reward the performance of confidence instead of the real thing.

That's why I keep saying the number is never the whole story, and it cuts both ways. It didn't tell the whole story about me, and it isn't telling you the whole story about the star on your team who hits every target while the people around them are quietly polishing their résumés.

So this week, pick one person you lead and look past the scoreboard for a minute. What's it like to sit next to them every day? Who's left their team this past year, and why did they go? That's data too; it just never makes it onto the dashboard.

Kara

P.S. Planning a team gathering for next year? I'm booking keynotes now, and the fastest way to start is to tell me a little about your event at karabundedunn.com/speaker.