In my 40 years of building businesses, hiring (and firing) key executives and managers, I've come across my fair share of what are known as "empty suits."

These are folks that appear polished, articulate, and always hard at work, but at the end of the day struggle to get done what needs to get done. They don't have what it takes to be an effective leader, despite the fact that everything on the surface would make you think the opposite.

Back when I was building my first company, Wilmar, I had a sales manager that was great at motivating. The only problem was, superstar employees don't need a cheerleader--they know how to motivate themselves. On the flip side, this particular sales manager had a hard time helping low or mediocre performers improve--because he didn't have the first-hand skill of selling or measuring key metrics. As a result, he didn't have much impact on the high-performing employees, because they didn't need it. And he didn't have much impact on the low-performing employees, because he didn't know how to help them.

And yet, he'd aced his interview. I had opted to hire him.

I have dozens of these stories in my book, All In. I've had executives that were so well read, they would "Wow" you in meetings with their knowledge--but when it came time to execute in the office, they would fail miserably. I've had CFOs that were great at "talking the talk" but couldn't effectively manage company financials. The hardest part about these kinds of hires is that you never realize the mistake until after some sort of damage has been done--especially if you're a startup.

What I've learned (the hard way) about these "empty suits" is this:

"Empty suits" spend their energy avoiding accountability, and, therefore, can't learn from mistakes they don't admit to. And because they never admit to mistakes, they end up overestimating their own abilities. This process then goes on and on.

Meanwhile, effective executives feel responsible for their outcomes, including mistakes they did not personally make. They feel invested, not just in their own success, but the success of the entire team and company at large--which is why their learning curve is dramatically accelerated. And consequently, they realize how much there is to learn, and in the best way, underestimate how talented they are.

In many ways, you won't know what an "empty suit" looks like until you've worked with an "effective executive," and vice versa. 

So, how do you ensure you spot the difference sooner than later?

Don't judge a book by its cover.

One of the worst mistakes you can make when hiring an executive or manager is basing your decision off what you see on the surface.

It can be easy to look at a resume or a lengthy history of working at big companies and assume the person sitting opposite you is the right person for the job. But there's a reason why I call these kinds of bad hires "empty suits." Just because they look the part, doesn't mean they can play the part.

When interviewing potential candidates, make sure you ask questions that prompt them to share lessons learned in the trenches. If the person you're hiring keeps speaking at a high level, keep nudging until they can give you specifics. And if you can't get them to share from personal experience, then make a note that you very well might be talking to a great cheerleader, but not a great executor.

Be upfront about expectations.

Too many hires get made for the position, and not the needs of the company.

If you're hiring a sales manager, don't just say, "We're looking for someone to manage our sales team." Explain exactly what it is you and the team need, and see if this is something your potential hire will be able to see through to completion. Be more specific. Say, "We're looking for someone to hold weekly internal sales workshops, and increase our team's overall performance by 10 percent in the next six months." 

Being upfront about expectations will not only make it easier to track performance and hold people accountable, but how they react to these expectations will give you a good sense of whether or not this person is right for the job.