(Daniel Acker/Bloomberg)

Some people might assume that the more money someone makes, the higher the credit score can be. But a new study suggests that thinking may be flawed.

The loan comparison website CreditCards.com looked at the average credit score for consumers in 25 major metro areas and found that cities with the highest median income did not necessarily have the highest average credit scores. It turns out that a much bigger factor affecting scores was how consumers used the credit that they had.

“Good credit is really more about discipline than it is about how much money you make or how educated you are,” said Matt Schulz, senior industry analyst for CreditCards.com.

The report compared the average credit score of each area with other demographic information such as median income, education level, average debt loads. It also looked at how heavily consumers use the credit they have available, which is the second-most important factor in determining a credit score.

The cities with the lowest average credit score were generally the cities where consumers had a higher credit utilization rate, or were using a bigger share of their credit.

For example, California’s Riverside and San Bernardino area had an average credit score of 624, and it was the lowest of the 25 metro areas studied. That area also had the highest credit utilization rate of 36 percent, which is higher than what lenders generally prefer. Borrowers should use no more than roughly 30 percent of the total credit they have available, credit experts say. So when consumers use more than that, even on a single credit card, their credit scores can take a hit.  

On the other end of the spectrum, the Minneapolis, St. Paul and Bloomington area of Minnesota had the highest average credit score of 704 and also the lowest credit utilization rate of 26 percent. (It tied with the San Francisco and Oakland metro area of California, which had the third highest average credit score of the areas studied.)

When you sort the 25 metro areas by income, however, the relationship to credit scores isn’t as strong. The city with the highest average credit score, Minneapolis, ranks sixth when it comes to earnings, with a median income of $69,111. And Pittsburgh, which had the fourth highest average score at 691, fell to the 23rd spot when ranked by pay, with a median income of $52,293.

To be sure, income isn’t directly factored into people’s credit scores. The way earnings may play a role in credit overall is that lenders look at it to decide whether to approve consumers for credit cards or other loans, said Ben Woolsey, president of CreditCardForum.com, an information and review website about credit cards. Therefore, people who earn more may have more credit available, making it possible for them to have a lower credit utilization rate than someone who has a similar debt load but less total credit available.

It’s also worth noting that the number one trait used to determine a person’s credit score, their payment history, was not measured in the study because the data was not available.

But the bottom line for consumers is that regardless of how much money you’re bringing in, the way to keep your credit score in check is to pay your bills on time — every bill, every month. And when it comes to using your credit, try not to use more than 30 percent of your total available credit — overall or on any single card.

Read more:

Three big mistakes Americans keep making with their money

What happens to your credit score when you close your oldest credit card

When it’s okay to let your credit score slip a little