It’s one of the first lessons you learn in business school: Loyal customers are the best customers. They love your brand, wouldn’t dream of switching banks and have been with you for years. Focus on loyalty and you’re sure to beat the competition, right?

Wrong.

Loyalty isn’t all it’s cracked up to be. While there is inarguably a benefit to having existing customers evangelize your brand, particularly in a social media world, loyalty as a single measure isn’t all it’s cracked up to be. In fact, strong loyalty is often a sign of underlying problems.

First, it’s important to look at loyalty for what it is: A look that sounds like it evaluates customer happiness but really measures how willing a customer might be to leave for another brand. “Loyal” customers can be the kind you really want, the ones who recommend your bank to friends, post on social media often about their experiences and go to your bank to buy more products and services from you.

Loyalty could just as easily be a measure of apathy. Think about it: When a customer says she is loyal, the assumption is that she’s perfectly satisfied with her service. But sometimes a customer just isn’t interested in making a move. It’s the law of inertia. Someone might want to switch to another brand, but the thought of cancelling an account, transferring assets and buying completely new products is just more trouble than its worth. Some customers might characterize an unwillingness to move as loyalty.

And then there’s the issue about generation. Customer loyalty is higher with older generations than, say, Millennials. In fact, research shows loyalty weakens consistently from old to young customers. For instance, data from Informa Research Service’s SEA Score, which measures member and customer engagement, show that those over 55 years of age – the Baby Boomers – are 37 percent more likely than Millennials to be loyal to their financial institutions. Or, stated the other way, Millennials are 73 percent less loyal than Boomers.

Knowing that, having high loyalty may correlate to having an aging customer base. While those are stable customers, they are often not growth customers, certainly not the ones who will be seeking new business loans, buying a vacation home or increasing deposits for saving. For those younger customers, loyalty doesn’t matter. They want competitive rates, a strong online experience, convenience and execution. The whole idea of loyalty is foreign to them, so any focus you put on loyalty in marketing to these high-growth customers is misplaced.

That isn’t to say that loyalty isn’t important. You obviously want to cultivate customers who remain with you for a long time. But it is a single data point. Without context, and a strategy beyond simple customer retention, you might be putting your future growth at risk.

Sue Hines is head of customer engagement at Informa Research Services, a provider of customer/member engagement and loyalty studies, competitive product rate and fee intelligence, and delivery channel experience measurements to the financial services industry.