It’s hard to really know from an interview whether someone is a good fit for your company. Resumés are fairly useless, and interviews are far from perfect. So we’ve come up with a better way to screen potential hires: a trial week.

Trial week is pretty much what it sounds like. After an initial set of meetings, we have candidates work at Weebly for a week. If things go well, they’re hired.

The trial week allows us to take chances on candidates who might not interview well and weed out people who make a good first impression but can’t back it up. In fact, trial week is so successful that in five years we’ve only asked two people to leave the company.

People are often surprised when they hear about trial week, but to us it makes a lot of sense. It’s hard to tell from a few hours of conversation what someone is really like or how good she is at her job. And it’s hard for a candidate to tell what it’s really like to work with us. Everyone preaches culture, but few really have a great one. We’re looking for people who intend to stick around for several years -- and that’s a big commitment -- so why not take the time to make a well-researched decision?

When we put it that way, very few people have declined to continue the interview process because of the trial week, less than 5% of applicants.

Here’s how trial week works:

We pay for everything. Candidates usually have to burn vacation time to participate in the trial week. So we want to make it worth their time. We fly them out, put them up in a hotel, and pay them for the week. I tell people that the worst case scenario is that they use a week of vacation, but because of the extra pay they can take a nicer vacation later on.

We have fun. Finding people who work well together is a big part of why we do the trial week. So we usually do a group activity, like a happy hour or go-kart racing. People are much more relaxed in these environments so you get a good sense of who they are. It’s an even better opportunity for the candidates. It’s easy when you’re recruiting someone to say how cool a company’s culture is, but there’s nothing like letting someone experience it.

We plan well. Trial week isn’t just culture. We want to see how productive people are. So we’re always prepared with a project for them to do. It’s real work, aligned closely with what the person would be doing if we hired her, and it’s designed to be more than one person can reasonably accomplish in a week. This isn’t just for engineers—we do it for hires in marketing and finance, too.

It’s not a competition. We recently had six engineers in for a trial week at the same time. We made it clear that our goal was to hire all of them.

Trial week started by accident. My co-founders and I couldn’t decide on our first few hires. We kept saying how it would be so much better if we could just have them come in and work at Weebly for a week before we made a decision. It was 2008. The economy was tanking, jobs were hard to find and people were willing to do it. We now have 90 or so employees, and people have a lot more options, but they’re still willing to do it.

It’s even worked to our advantage. After completing the trial week with us, many candidates felt like the interview process at larger companies was too impersonal and they couldn’t picture working there.

Trial week allows us to be more open minded when we interview people. There was one engineer not that long ago who was pretty bad at answering CS questions during an interview. We don’t ask brainteasers like how many golf balls can fit in a school bus -- that’s not what we’re screening for -- but he was struggling to answer basic stuff.

If we had to make a decision based on an interview we wouldn’t have hired him. But he’d done a lot of great work before, so we thought he might just be nervous. We brought him in for a trial week and sure enough he destroyed it.

We’ve also had people that we thought would be great but turned out not to be. We recently had two people who were rude to our office manager during the week. That doesn’t fly. Some people just aren’t productive enough.

Our hire rate out of trial week is around 66%, which feels like the right level.