How do you measure brand loyalty these days? Is it through rewards? Mobile users? Traffic? For restaurant brands, the reality is that question has never been more convoluted. Many companies have simply cut bait and decided brand loyalty is dead. But studies have shown the opposite to be true, even among the much-maligned millennial generation. A Facebook IQ survey last year showed that millennials are just as likely to be brand loyalists as Baby Boomers—the demographic most often categorized as creatures of habit.

A study of 14,700 U.S. consumers reported that millennials were twice as likely as Boomers to cite a lack of healthy options as a barrier for loyalty, and that taste is the No. 1 reason given for why a consumer sticks to a certain brand. Technology was also key. Overall, the sentiment is simple: consumers of all generations do care about the logo on the front of the building

Foursquare recently released its Quick-Service Restaurant Loyalty Index. The company ranked the top 50 chains in the U.S., according to customer loyalty. The location intelligence platform got there by measuring foot traffic in four metrics: visit frequency (the average number of visits per diner within a year); market penetration (the percentage of all quick-serve diners who visited the chain with a year, measured for regions in which the chain exists; share of wallet (the percentage of a customer’s total quick-service visits that a particular chain captures within a year); and fanaticism threshold (the number of visits within a year required for a customer to be within the top 1 percent of customers who visit a particular chain, on a scale of 1 to 50).