Tia Chambers checked her credit score for the first time at age 23, after watching a friend check his, she says.

“I said, ‘Oh boy, my credit score has to be better than that,'” says Chambers, now 31, who blogged about her experience on her website, Financially Fit and Fabulous. To her surprise, it was worse. “My credit score was a lot lower than I expected. It was actually in the mid- to high 500s.”

She felt deflated. “I thought, ‘Man, I pay my bills on time. Why isn’t my credit score higher?'”

If you’re new to credit, you might wonder the same thing. Why does your credit score pale in comparison to your friend’s, even though you checked it on the same website, using the same scoring model?

“For someone who has a low credit score, there is always — and I mean always — a logical explanation for why that score is the way it is,” says John Ulzheimer, a credit expert who formerly worked for credit-scoring company FICO and credit bureau Equifaxe. “It’s never random. It’s never anecdotal.”

These factors might be working more in your friend’s favour than in yours:

CONSISTENT RECORD OF ON-TIME PAYMENTS

You and your friend might be in the habit of paying bills on time, but even one forgotten payment can drag down a credit score .

That’s part of what happened to Chambers, of Indianapolis. When she checked her credit report, she says, she discovered a forgotten unpaid medical bill in collections. She paid it, negotiated to get the collections account removed from her credit report and noticed a slight lift in her score afterward, she says.

Payment history is a key factor for both FICO and VantageScore Solutions, the two major credit-scoring companies in the United States. It accounts for 35 per cent of your FICO score, and VantageScore characterizes it as “extremely influential.” Payments more than 30 days late are reported to the credit bureaus and, like other negative marks, can stay on your credit report for seven years.

“(A negative mark) is much easier to avoid in the first place, rather than trying to get it off after it already has happened,” Ulzheimer says. If you negotiate with a collections agency to get a collections account removed from your credit report, get that promise in writing.

LESS DEBT

If you never talk to your friends about money, you might not realize that their financial situations are different from yours. Becky with the good credit score might have less debt than you.

Using a smaller percentage of your credit card’s available limit and paying down student loans can boost your credit . The amount you owe accounts for 30 per cent of your FICO score. For VantageScore, percentage of credit used is a “highly influential” factor, and total debt is “moderately influential.”

Chambers says she worked second jobs and trimmed spending to pay down her high credit card balance and thousands owed to her college.

“I saw at least 100 points improvement by the time I paid off that debt,” she says.

LONGER CREDIT HISTORY OR VARIED ACCOUNT MIX

Your age, gender, sexual orientation, race, location, religion and political views don’t affect your credit score. Having a high income won’t goose your score, either.

So what else counts? The length of your credit history, for starters. This makes up 15 per cent of your FICO score and is “highly influential” for VantageScore. Your friend may have started using credit earlier than you did.

Applying for new accounts can also ding your credit, but generally only a little. Maintaining a mix of accounts — for example, carrying both loans and credit cards — can help.

STEPS TO IMPROVE YOUR CREDIT

To see what’s hurting your scores, pull your credit reports for free from AnnualCreditReport.com, a federally authorized website. Then, take these steps:

—Dispute inaccuracies. Report errors on your credit reports to the corresponding credit bureaus.

—Pay down debt. In particular, reducing high balances on credit cards can boost credit significantly.

—Piggyback. If your parents have excellent credit, ask them to add you as an authorized user on a credit card.

—Open a credit card and use it responsibly. Start with a student card or a secured card, one that requires cash collateral. Those under 21 may need a co-signer.

Finally, don’t pay too much attention to what others are doing. Credit scores vary because people’s financial paths vary. “Everyone’s journey is different,” Chambers says.

_______________________________________________________________

This article was provided to The Associated Press by the personal finance website NerdWallet . Email staff writer Claire Tsosie: claire@nerdwallet.com . Twitter: @ideclaire7 .

RELATED LINKS:

NerdWallet: Virtual people, real lessons: How card use affects credit score

https://nerd.me/2s6yxjV

NerdWallet: Add 100 points to your credit score

https://nerd.me/2skeVed

Financially Fit and Fabulous: How I raised my credit score 150+ points

http://www.financiallyfitandfab.com/raised-credit-score-150-points/

Claire Tsosie, The Associated Press