Hiring the wrong candidate gets costly. From costs incurred by drops in productivity, to reputation costs, hiring the wrong candidates can set your business back in deep and lasting ways, reports Entrepreneur.

Being in the staffing industry for 13 years now in the high volume clerical and light industrial sectors, I’ve seen my fair share of right hires vs. wrong hires. It comes down to four key principles.

1. Let the interview speak for itself.

Ask integrity-based questions, performance-productivity questions, and form them in always open-ended ways. This is your time to get to know the candidate, and to see the important bits: not what they say on paper, but how they react on the spot.

Smartt tip: ask questions from the perspective of your interviewee’s potential coworkers. They are your proverbial canaries in the coal mine, in that they are the most likely to see red flags before management, who don’t work on the ground with a new hire, will. A good candidate will own up to not knowing certain answers, without getting overly self-conscious about the knowledge gap. Overconfidence can sometimes be an important factor, too. Trust your gut.

2. Core values.

Your company has spent a wealth of effort building your mission and vision, and grooming your employees to fit your culture. Making sure your prospective employees are a culture fit is arguably the most important issue to consider on your hires. Candidates with less experience but a deep commitment to your company’s values often learn faster, require less hand holding, and devote themselves with better outcomes than those who aren’t culture fits.

Smartt tip: if you’re having trouble reaching concord with a new hire, talk with your other employees. Ask them questions in the vein of barriers to their own success. If you see correlations, pursue them.

3. Don’t make it all about the paperwork.

You’re fostering a relationship here, not filling out papers. They’re important, and definitely get them filled out, but please do yourself a favor and make the on-boarding process more about getting to know the team, the off-paper processes, and integrating with a new work-family than focusing on a mid-20th century stodgy HR desk experience. You can make sure all the appropriate boxes are checked without losing the humanity in the situation.

4. Productivity matters.

According to Stuart Brown,“the estimated costs of losing an employee vary wildly, from 30% of annual salary, to as much as 200 times annual salary for high level positions.” Consider how confident you feel in how well your new candidate can get up to speed without taxing other workers.

Smartt tip: consider how robust your training materials are, and work toward a seamless integration.

Hiring the right candidate is a better question, really, but it’s much harder to answer. If you can identify “wrong” clearly, you’ll be in a better position to determine what your particular “right” is. Happy hunting!