(Bloomberg) -- What’s the difference between Coke and Pepsi? For job seekers: Coca-Cola Co. offers the best career mobility out of nearly 400 big employers, according to a new five-year analysis of 4.7 million workers. Rival PepsiCo Inc. came in 19th on that same list. 

The American Opportunity Index — a product of Harvard Business School, the Schultz Family Foundation and Burning Glass Institute, a labor-focused nonprofit — measured how millions of workers fared at companies by looking at hiring, pay and promotions, particularly among entry-level and lower-skilled workers. By tracking their trajectories, the analysis determined which companies pay better wages for workers in similar roles or promote their people most equitably.

Also in the top 10 were jelly maker JM Smucker Co., tech behemoth  Meta Platforms Inc. and retailer Costco Wholesale Corp. 

The index could provide guidance for young job seekers looking to work at a company that considers their career progression, rather than simply providing platitudes like: “Our employees are our greatest asset.” It could also come in handy for those making a mid-career move to a new occupation or industry. With hiring slowdowns and layoffs, workers are putting a higher premium on employers that offer career longevity. Employers, meanwhile, stand to benefit if they can hire and develop more workers outside of their normal recruiting pools, and lower the rate at which employees leave for other opportunities. 

The makers of the index, now in its second year, claim it’s the “only measure of employer quality evaluating what really happens to workers at America’s largest employers over time,” adding that high scores can translate to the bottom line. Moving from the worst-performing quartile to the top on employee retention, for example, can save a company as much as $424 million a year in costs related to turnover, the authors estimate. There’s a payoff for workers, too: Those at the top-ranking firms get paid 68% more, on average, for the same jobs. 

The ranking makes some revealing comparisons between companies and industries. Costco, for instance, is 42% more likely to retain its workers over three years than rival retailer Target Corp., while Microsoft Corp. is 20% more likely to hold onto staff across three years longer than Oracle Corp. Airlines have some of the worst rates of gender equality, while banks and telecom firms are good at promoting internally. Retailers excel at hiring people without degrees or experience, but technology firms are difficult to break into without such qualifications.

Coca-Cola, which employs more than 82,000 people globally, ranked first overall thanks to top-quartile performance on pay, hiring and corporate culture. In this case, “culture” includes things like retention and whether leaders are found from within. Lisa Chang, Coca-Cola’s global chief people officer, said the company encourages employee mobility by letting workers embark on short-term assignments, often in another business unit or geography. 

Last year, AT&T Corp. topped the list, but this year it finished 64th. None of the companies in 2022’s top 10 remained there this year, which is partly due to the addition of more companies and new metrics, such as wage growth and gender parity.

The Schultz Family Foundation is the philanthropy started by longtime Starbucks Corp. leader Howard Schultz.

--With assistance from Brett Pulley.

(Updates with details on Schultz Family Foundation in final paragraph.)

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