You Need a Strategy If You Hope to Keep Your High Performers If your most ambitious people don't see a path forward, they will look for a path out.

Everyone loves high performers. They're driven, dedicated to their work and constantly on the lookout for growth opportunities. It only makes sense that employers would go to great lengths to keep their top employees. But the fact is high performers are leaving their employers just as often as low performers are -- and not in small numbers, either. One in five top-performing employees is likely to leave his or her job in the next six months.

To make the business implications even clearer, a high performer is 400 percent more productive than an average employee. And if you need to replace that talent? The full cost of turnover -- including hiring costs, training costs and the time lost getting a new employee fully up to speed -- is staggering. Throw in the scarcity of top talent, combined with the very real struggle for companies to secure that talent -- 82 percent of Fortune 500 executives don't believe they recruit highly talented people -- and the stakes of preventing turnover become even higher.

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So what can you do to retain your high performers? The first step is noticing if they're about to make a shift.

A flatlining trajectory can push high performers out.

A major part of what makes high performers so great is that they aim high and keep an eye on the future. So when they stop seeing that same trajectory in their own careers, it's no surprise they'd start looking for new opportunities. Across the board, more than 70 percent of employees who plan on leaving their company within the next two years say they have to leave their organization to advance their careers. For high performers, advancement is also at the forefront of their minds: Along with salary, it's their top reason for quitting. How can you tell? When your top employees can't see a path forward in their current role, they're actually likely to have fewer career progression conversations because they're already thinking about their next steps out the door.

When high performers commit to something, they do it right. But when they're thinking about making a shift, these same employees are likely to avoid taking on new responsibilities, particularly if they have a long horizon. Sure, your top employees will still fulfill their obligations, but whether they've committed to projects at work or extracurriculars, they won't be adding to their plates -- and they might be only put in the minimum amount of work. A side effect? Taking on fewer responsibilities can also make your best employee seem like less of a team player than usual.

While you won't necessarily notice a dip in performance with a high performer who's starting to think about leaving, you'll absolutely notice a dip in enthusiasm, both for his or her work and for the company mission. Because a shared purpose can be such a strong driver of engagement in the workplace, a high performer not buying into the vision -- or not having confidence in managers -- can have a snowball effect, creating an even greater disconnect between the employee and the company.

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If you spot these warning signs, what can you do to try to keep a high performer on? Of course, there are always the "hail mary" efforts most companies try like raises, promotions and additional flexibility -- and pay definitely is still an important piece of the puzzle. But these efforts may only be a temporary Band-Aid to mask the problem at hand.

What actually works?

Put blockers on burnout.

High performers are put on the hardest projects -- over and over again. You know they can deliver and really, it's only logical to put your best people on the most important projects. But when top employees are under constant pressure while also being asked to help out with smaller ad hoc tasks that aren't related to their work, these demands can be a fast track to burnout. Communicating with your high performers and taking the time to rein in some of these additional projects and requests will not only show your top performer that you are a source of support who values their time, but it'll also clear their desk to work on the projects that really matter.

Recognize their accomplishments.

No one likes to feel like work is being taken for granted. And for top performers who are frequently called to step up to compensate for weaker employees, it's even more important that they know that their work is valued. They aren't just "entitled" millennials who want a pat on the back. In fact, recognition has been found to be one of the most impactful drivers of employee engagement, though not every method of recognition is equally valuable. An "employee of the month" award or even an exceptional annual performance review just isn't going to cut it. Instead, what will be much more meaningful to your high performers is to look for frequent and specific opportunities to recognize the value of their work.

Related: 4 Things That Are Keeping You From Hiring the Best Talent

Provide immediate opportunities for leadership growth and advancement.

While recognizing a high performer's accomplishments can go far to increase an employee's ties to an organization, recognizing a young employee's potential to grow into a leadership role is just as important to show that you're invested in their advancement. And lest we forget, a lack of opportunities for advancement is one of the main factors influencing turnover. A necessary starting point here is to have a one-on-one with your high performer to discuss long-term goals. From there, you can seek out learning opportunities for your high performers to gain exposure to things they're interested in. Providing access to key senior sponsors at the company and getting your top employees engaged with more powerful leaders can also yield a lot of benefit.

I'm not saying that it's easy to keep your high performers. But when losing your top talent comes at such a high cost, it's more than worth the effort to diagnose signs of turnover and take steps to keep your best employees on board. You'll not only retain your rising stars, but you'll also encourage their long-term professional growth. That said, if you're not taking the time to listen to your employees, you're not going to pick up on any of these things in the first place.