The 2016 Best Places to Work list is a joint effort of Advertising Age and Best Companies Group. The latter is dedicated to establishing programs to identify and recognize workplaces that nurture a superior level of employee satisfaction and engagement. Companies from across the United States participated in the two-part survey process to determine Ad Age's Best Places to Work. Any agency, ad tech, media company or marketing division of a brand that's been in business for more than one year with more than 15 full-time employees was eligible. Public, private, for-profit and not-for-profit businesses could all participate. The list was determined by feedback from two surveys. The first garnered information about employer offerings, and the second was an employee survey to measure the workplace experience. The combined scores determined the top companies and the final ranking.
See the full list here: http://adage.com/article/news/ad-age-s-places-work-2016/306695/