If you ask business leaders what they think are the most important things to look for when hiring someone, you'll get a lot of answers. When I work with companies, I often hear things like "takes initiative", "works well on a team", "great problem solver", "knows the business", "brings experience", or "fits with our culture."

All of these are really important, but without one key additional characteristic you might find yourself with a good hire who does well but doesn't quite achieve the potential you want or show the ability to continuously grow with you.

So what is the missing ingredient? It is the ability to learn, and some have even identified it as the single best predictor of someone's potential.

Simply defined:

"Learning agility" describes a person's speed to learn. It focuses on willingness and ability to adapt to new situations by using things already learned in other situations. In other words, it represents how well a person transfers learning and knowledge from one experience to another completely new experience.

Critical for small companies

Change is an inevitable part of growth. As my own company has grown, I've had to make continuous adjustments to strategy and approach every year based on business development successes and failures and a slew of other things I couldn't really plan for. And the skill sets of the people I've needed to work with me have evolved as well.

I also work with many smaller companies where things develop that cause them to completely change what they were doing, shift strategy, re-work their operational infrastructure, or evolve products in a way that wasn't anticipated.

Trying to find someone with all of those experiences would not only be really hard but wouldn't really be that valuable anyway because no one really knows what the next challenge around that blind corner is going to be anyway.

One of the biggest mistakes I see small companies make is hiring people for the immediate need but not thinking about whether the person has the potential to grow.

How do you assess learning agility?

Here are four things you can do:

1. Interview for it

If you've read any of my previous articles, you know that I'm not a huge fan of the interview. It is flawed in many ways, but there are some good questions you can use.

Focus on questions that force the candidate to talk about a real situation where they had to take on a new challenge or figure out how to adapt to something unexpected.

2. Assess it with an instrument

Many companies are starting to use assessments. Lots of HR firms, leadership firms, and executive search firms have their own versions of learning agility assessments.

These are all validated assessments that can give you less biased and more accurate views of a candidate's ability to learn and adapt.

3. Reference check for it

Sometimes the reference check just becomes a check the box process. If you do it right, though, you can get some great insight because you are talking to someone who has real work experience with your candidate. Granted, the person was also referred to you by the candidate him or herself, so there is inherent bias in it.

That being said, a focused reference check with targeted questions about situations where the candidate had to adapt and learn quickly can actually yield some surprising and insightful answers even from references that the candidate provided to you.

4. Throw something new at the person as part of the selection process

The simplest and most objective way to do this is to build a mini assignment into the selection process. It can be a quick case study scenario where the candidate must work through something unknown and generate a product within a time boxed period.

Other companies have gone a step further by having one of the interviewers throw a curve ball at the candidate by being purposely difficult or challenging to see how the candidate adjusts.

It's not a comfortable situation for the candidate (I can attest to this from having gone through a few interviews that were structured this way) but an excellent way to see real time behavior adjustment on the fly.

So as you continue to grow your company, don't forget to really focus your selection process on finding people who can grow with you instead of just fulfilling your current needs. And the only way to do that is to really hone in on just how fast, capable, and wiling your candidate is at learning something new.