No matter how many interviews you've conducted, matter how many people you've hired, hiring new employees can seem more like art than science.

No approach, no strategy, no process -- and definitely no single interview question -- is foolproof. 

But some rules do apply.

The 1st Rule of Hiring: You Will Get It Wrong

We've all hired people we just knew would be superstars who turned out to be duds. And we've all passed on people who turned out to be superstars at another company.

If you're like me, you regret the ones you let get away more than the ones you had to let go.

No matter how many interviews, no matter how many reference checks, no matter how comprehensive your process, some hires won't make the grade. Or be the right fit.

Anyone who says otherwise hasn't hired many people. Or is delusion.

Which is why ...

The 2nd Rule of Hiring: Hire Fast and Fire Slow

The more popular phrase is "Hire fast, fire faster." 

Even the American Management Association agrees, saying, "Selecting a bad hire is understandable; but accepting it and not doing anything about it will cost an organization greatly." 

Yet sometimes seeing the good in other people -- before they see it in themselves -- provides the spark that helps them reach their true potential. After all, most people don't try to underperform. Most people don't try to do a terrible job. In almost every case, something is missing. A little extra training. A little extra encouragement.

A little extra sense of belonging, and meaning, and purpose.

Fire too fast and you may let go a potential superstar -- and replace him or her with another person who is not guaranteed to succeed either.

The 3rd Rule of Hiring: Employees Will Always Share How Much They Make

Many companies actively discourage their employees from talking to one another about their salaries. Some even ask employees to sign agreements stipulating they won't disclose pay, benefits, etc. to other employees.

Yet people almost always talk. I did, both when I was "labor" and "management." Generally speaking, the only employees who don't share details about their pay are the ones who are embarrassed by how much or little they make.

Never assume raises, bonuses, starting salaries, perks--basically anything related to compensation--will stay confidential.

Why is why ...

The 4th Law of Hiring: Lowballing Always Backfires

Occasionally the job market is a seller's market, but many new employees are delighted to land the new job. And since business owners are born cost-cutters, it's natural to want to pay new hires as low a wage as possible.

But when the employment honeymoon wears off and the employee feels you took advantage, that feeling never, ever disappears.

Ultimately, an employee's pay should reflect their value to you. Not what they made at their last job. Not what they're willing, for whatever reason, to accept.

Pay people what they're worth and they're much more likely to give you what they're worth.

The 5th Law of Hiring: Nobody Really Knows Anything

A great interview isn't an indication of future performance. Nor is charisma. Or personality. Or appearance. Or, really, anything.

A superstar at her last job can quickly be demotivated by a terrible culture. A superstar at his last job can become subpar overnight if the job isn't a good fit. A mediocre performer at her last job can become a superstar at your company if the purpose and meaning of her work strikes a genuine chord within her.

Plenty of people have joined a company only to find out it wasn't what they thought. The job itself was different than advertised. The culture was different. The responsibility, or autonomy, or opportunities were different. 

So while experience can help improve your odds of making reasonable hiring decisions in the aggregate, on an individual basis, no one really knows anything.

Which can be your competitive advantage. Since you can't know, you can afford to take a few chances. You can look for employees where others won't look.

You can hire for attitude, not skill -- and trust your ability to teach the needed skills. You can hire for enthusiasm, not experience -- and trust that time and effort will result in experience that truly pays off in terms of performance.

Since it's impossible to know how things will work out, why worry? Why hesitate? 

Take a shot. Take a chance. Analyze and assess, and then add a little gut feel to the mix.

Because you never know.

Which means you might as well take a few chances.