The link between employee satisfaction and productivity is simpler than you think.

Every year, Glassdoor compiles a list of the “Best Places to Work.” The good people over at Glassdoor measure the quantity, quality, and consistency of employee-submitted reviews for companies across the nation, and the globe, to come up with a comprehensive catalog of 50 companies that employees absolutely adore. It turns out, the same companies that make the Best Places to Work list, also top out the S&P 500 according to CNBC. Coincidence? We think not.