The unmysterious credit score

This guest post comes from Frank Curmudgeon at Bad Money Advice.

In certain circles there has always been plenty of discussion of credit reports and scores. But since the Great Recession, interest in the topic has grown to the verge of mainstream consciousness. Ordinary folks now routinely consider the credit score impact of their actions, including such esoteric issues as the undesirability of closing unused credit card accounts. (It increases the ratio of used to available credit, which is bad.)

But through all this it seems as if the underlying point of credit scores has been lost. It is not a game with arbitrary rules meant to keep consumers on their toes. Nor is it a measure of virtue.

If you are in the business of lending money, what you want to know about a potential borrower boils down to a simple question: Will this person pay me back? Credit scores do nothing more than give a probability that a borrower will make good, based primarily on his history of paying other people back, but also considering such measures of financial stress as how many times he has asked for a loan recently and the credit lines to credit used ratio mentioned above.

• Bing: What good is a good credit score?

It is easy to get lost in the details of how credit scores are calculated. (Or how we think they are calculated. The exact formulae are secret.) Geeks like me who find joy in the weird crannies of the tax code are particularly susceptible to this. But if you spend too much time trying to game the system, you tend to miss the forest for the trees, forgetting the underlying purpose and logic of credit scores.

• Estimate your credit score

I am reminded of this by a recent post at The Consumerist that shared the apparently non-obvious tip that "letting mortgage go delinquent to qualify for short sale damages credit." In what alternate reality could skipping mortgage payments not damage your credit? For that matter, how could a short sale, in which a borrower settles a debt for less than what was owed, not damage credit?

This inexplicable confusion about the effects of not paying your mortgage as agreed has been something of a recurring theme. Back in December, when some people still thought Obama's mortgage modification scheme would have significance, CNNMoney.com broke the news that mortgage modifications are bad for credit scores. This was, apparently, a shock to some of the participants in the program and even to some of those running it.

There is an emotional issue here. Homeowners with more mortgage than they can afford consider themselves to be the victims of circumstance. By and large, they did what all the personal-finance advisers told them to do. And it seemed like everybody else was buying big houses with big mortgages. Then things went bad and, poof, they owe more than they can pay.

I am not entirely unsympathetic to this. Penalizing a homeowner for doing what he was "supposed" to do but at the wrong place and time is not as fair as dinging a consumer who blithely runs up credit card balances he cannot afford.

But fair is not what credit scores are about. They do not consider morality, justice, or virtue. All a potential lender wants to know about is the likelihood of being paid back, and the first indication of that is the borrower's history of paying others back. Failing to fully repay a loan is bad. Why that happened, be it carelessness, greed, or even well meaning but naive foolishness, is relatively unimportant.

• Video: A great credit score won't cut it for loans

The fact of the matter is that, despite everything, the vast majority of homeowners have managed to stay current on their mortgages. Those people will have an easier time borrowing money in the future than those who did not. Which is as it should be.

At the detail level, credit scores are complex and even mysterious things. But in the big picture, they are simple. Lenders like borrowers in the habit of paying back loans. Like many things in life, if you want others to trust you, be trustworthy.

More from Bad Money Advice and MSN Money:

• Why you haven't strategically defaulted yet
• Mortgage, car loan, credit card: Pay any 2
• The usefulness of ID theft fear
• Loan modifications hurt credit scores
• How 5 money blunders ding your credit
• Do bad employees have bad credit?