by Christine Porath

Nothing is more costly to an organization’s culture than a toxic employee. Research shows that rudeness is like the common cold — it’s contagious, spreads quickly, and anyone can be a carrier.

Dylan Minor, a visiting assistant professor at Harvard Business School, and Michael Housman, chief analytics officer at Cornerstone OnDemand, studied just how costly toxic employees are using a large dataset of nearly 60,000 workers across 11 firms in various industries, including communications, consumer services, financial services, health care, insurance, and retail.

How does hiring a toxic employee compare to hiring a superstar? Minor and Housman found that one toxic employee wipes out the gains for more than two superstars. In fact, a superstar, defined as the top 1% of workers in terms of productivity, adds about $5,000 per year to the company’s profit, while a toxic worker costs about $12,000 per year. The real difference could even be greater if you factor in other potential costs, such as the spread of the toxicity, litigation fees, lower employee morale, and upset customers.

I’ve shown something similar in my research on civility at work: rude workers have a stronger effect on the organization than civil workers. That’s why it’s especially important to weed out toxic people before they join your organization. Here’s how:

  1. Interview for civility
  2. Get your team involved
  3. Ask their references about civility
  4. Check your own civility