原文在这里,由于太长了,又是E文的,只节选我觉得有用的信息过来了http://www.bankrate.com/yho/news/credit-scoring/20031104a2.asp

Key factors of your score

Just what goes into the score? Everything in your credit report, with different kinds of information carrying differing weights, says Fair Isaac consumer affairs manager Craig Watts. The model looks at more than 20 factors in five categories.

1. How you pay your bills (35 percent of the score)
The most important factor is how you've paid your bills in the past, placing the most emphasis on recent activity. Paying all your bills on time is good. Paying them late on a consistent basis is bad. Having accounts that were sent to collections is worse. Declaring bankruptcy is worst.

2. Amount of money you owe and the amount of available credit (30 percent)
The second most important area is your outstanding debt -- how much money you owe on credit cards, car loans, mortgages, home equity lines, etc. Also considered is the total amount of credit you have available. If you have 10 credit cards that each have $10,000 credit limits, that's $100,000 of available credit. Statistically, people who have a lot of credit available tend to use it, which makes them a less attractive credit risk.

"Carrying a lot of debt doesn't necessarily mean you'll have a lower score," Watts says. "It doesn't hurt as much as carrying close to the maximum. People who consistently max out their balances are perceived as riskier. People who never use their credit don't have a track history. People with the highest scores use credit sparingly and keep their balances low."

这里还有一个补充:Lenders look at how much available credit you actually use. Keep your credit card use to less than 30% of your credit limits. So, if your card carries a $500 limit, try to keep your spending below $150 -- even on a secured credit card. Not only will this strategy help you to get the best possible rates, it can help you avoid getting in over your head in debt

3. Length of credit history (15 percent)
The third factor is the length of your credit history. The longer you've had credit -- particularly if it's with the same credit issuers -- the more points you get.

4. Mix of credit (10 percent)
The best scores will have a mix of both revolving credit, such as credit cards, and installment credit, such as mortgages and car loans. "Statistically, consumers with a richer variety of experiences are better credit risks," Watts says. "They know how to handle money."

5. New credit applications (10 percent)
The final category is your interest in new credit -- how many credit applications you're filling out. The model compensates for people who are rate shopping for the best mortgage or car loan rates. The only time shopping really hurts your score, Watts says, is when you have previous recent credit stumbles, such as late payments or bills sent to collections.

"Then, looking for new credit will be seen as an alarm because statistically, before people declare bankruptcy and default on everything, they look for a life preserver," Watts says. Also, if you have a very young credit file, an inquiry can count for more than if you've had credit for a long time.