2 things the best companies do to keep their employees happy

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When people say they love where they work, that's an incredible win for the organization. The businesses getting ahead in today's competitive markets know this and gain a unique advantage by putting their people first.

For 20 years, Great Place to Work has ranked the best employers across all sectors of the economy. In that time, the growth of a hypothetical portfolio of the Fortune 100 Best Companies to Work For list has outpaced the Russell 1000 index by more than double.

These companies have figured out how to create work environments that tap into the full potential of all their employees. That translates into engaged workers, collaborative teams and higher levels of innovation – all essential components of a successful enterprise.

Our research, which includes 229,000 surveys of leading workplaces, shows that people who feel they have a standout employer are four times more likely to say they give extra to get the job done.

In fact, 84 percent of co-workers at the 100 best companies also say they look forward to coming to work. That level of day-to-day productivity and commitment shows why a strong organizational culture is such a valuable asset.

Then there's turnover: We've found that leading employers experience voluntary turnover rates 50 percent lower than their industry peers. In fact, 87 percent of people at the best workplaces say they plan to stay for the long haul. And millennials, a generation known for switching jobs often, are more than 25 times more likely to say they plan to stick around when they feel they have a great place to work.

Here are two ways the best companies keep their employees happy:

They do more than just offer flashy perks

Often, business leaders assume that Silicon Valley-style amenities (think "nap pods" at Google or the decked-out game rooms of Web startups) drive a positive work experience. But again and again, our research confirms that admiration for the leading companies runs deeper.

Regardless of their benefits, the best workplaces share cultures built on trust. Their people know they can count on peers and managers for support and that their work will be judged on its merits alone.

They pay their employees fairly

Revenue grew substantially faster at leading workplaces that demonstrated a commitment to inclusion and equal treatment, according to our research. That's because people work harder when they're confident advancement is tied to performance, rather than office politics or the arbitrary judgment of managers.

To make organizations more equitable, businesses like Adobe have dropped annual employee reviews in favor of ongoing, two-way feedback with supervisors. Other fairness initiatives by leading employers include unconscious bias training and bonuses based on group, rather than individual, performance.

Teams also pull harder together when all their members can see opportunities for professional growth. At AT&T, for instance, 140,000 people are taking part in education programs preparing them for new roles as technology reshapes their industry.

Every business must find its own set of tools for leveling the playing field, but the end result is the same: a high level of trust. Companies are more united around their goals when all employees believe they can get ahead on their own merits.

The result is more than just a welcoming place to do business – a great work environment is a very real factor in how quickly a company can grow its earnings.

Michael Bush is the CEO of Great Place to Work.

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