The economy is still strong. Companies' hiring plans for 2019 reflect that. ManpowerGroup's Employment Outlook Survey found that all 13 industries surveyed anticipate increased hiring in 2019, many in the double digits. Employer optimism is at a 12-year high, and a tight talent market is about to get tighter.

When competition for employees heats up, companies on the hunt for superstars sometimes skip their due diligence. That can result in bad hires that waste money, slow productivity or hurt morale -- and the last thing a fast-growing company needs is a drain sucking the energy out of the team.

It's true that one team's rock star might not be another team's cup of tea. But there's one type of employee that can wreak havoc on just about any workplace.

A Silent Killer

Even truly terrible hiring managers don't hire angry or apathetic employees -- we're not talking about common red flags people actively avoid. No, the worst type of employee you could hire is one who will sneak in undetected: the employee who doesn't care about others.

Empathy is an indicator of someone who views the world through healthy eyes. People with high EQ think about how their actions will impact other people and are able to read how others are feeling. They can feel genuine joy or sorrow for their teammates, and they care about making things better for those around them.

In work terms, these are the people who will pitch in to help teammates when their own work is done. They're the ones who will help you brainstorm solutions for a difficult problem. They'll take an extra second to think about how to include a new team member or someone who's been out on medical leave. They won't coddle, however, and that's an important distinction.

People who lack an interest in others, on the other hand, can silently erode a team. People who don't have compassion or consideration for the people they work with, day in and day out, will step on teammates for promotions or leave them hanging with important deadlines. As long as their nose stays clean, they don't care. And once they've cleared the obstacles in their path (their teammates), they'll set their sights on you.

The tricky part is that people lacking empathy can hide their inability to care about others during the interview process. Here are a few things to dig into to determine whether you're inviting a morale killer into your flock:

  • Ask situational questions. Don't lead candidates' answers with the phrasing of your questions, but ask how they'd handle certain scenarios: You can tell a teammate is behind and about to blow a deadline for the whole team. What would you do? You see a co-worker stuck in a frustrating pattern -- what's your next step? With answers that can range from ratting out a co-worker to creating a new safety net, you can learn a lot about candidates' perspectives.

  • Mention a detail that should elicit empathy. I'm not advocating for tricking interviewees, but a non-reaction to a real event should raise red flags. When telling a story or explaining a process, you can easily weave in a setback or unexpected event that happened: a missed flight, a stock market crash, an ended partnership. What happens next will give you some insight.

  • Determine their big motivators. People get into industries or hold roles for very different reasons. There are no right or wrong answers, but hearing about prospective employees' strengths, setbacks and "why" can give you a clearer picture of how they operate. It can also help you anticipate future behavior. One person I interviewed told me she'd actually ended up in sales because she met a pharmaceutical sales rep when helping a sick relative. That sales rep's behavior convinced her that people could use their powers of persuasion for good, not just personal benefit. It wasn't the answer I was expecting, and I eventually hired her for her talent and interest in boosting others.

  • Aim to set a casual tone. Once people are comfortable, they'll reveal more bits and pieces about themselves. Chris Powell, the CEO of Talmetrix, experienced this firsthand when he worked in HR at Scripps. When discussing a problem, another employee said to him, "Chris, we only have to appear to care." Powell told my colleague Heather R. Huhman in 2017, "At that point in time, I realized I hired the wrong person."

There are a lot of ways leaders can end up hiring the right people -- or the wrong ones. But people who lack empathy should never make it through the door. The divides they can create - without even caring or trying to -- aren't worth the growth they can fuel.