CLEVELAND -- If you have a car, a house or a credit card, you've worked hard to achieve an acceptable credit rating.

But Troubleshooter Chris Caswell reported that reporting agencies can issue wildly different scores about your credit history.

The Consumer Federation of America and the National Credit Reporting Association studied 500,000 consumer credit files. They found many errors among reporting agencies that can prove costly for consumers.

If you're applying for a credit card, car insurance, a cell phone, or almost anything these days, someone is looking at your credit report.

"We believe the growing use of credit scores is a positive trend, because it clearly increases the efficiency of credit granting and also appears to increase its fairness," said Stephen Brobeck, of the Consumer Federation of America. "But because of the importance of these scores, it is extremely important for them to be accurate.

"We estimate that as many are being advantaged as disadvantaged, and our point is this should not be allocation of credit or other important services should not be based on a lottery system."

Three companies -- Equifax, Experian and Trans Union -- provide credit reports. The study found that not one is better than the other.

"NCRA believes the three credit repositories do an admirable job of maintaining the credit information of 190 (million) to 200 million consumers," said Terry Clemens, of the National Credit Reporting Association.

To protect yourself, experts recommend getting a copy of your report at least once a year.

Call the three major credit-reporting agencies: Equifax at (800) 685-1111, Experian at (800) 333-4930 and Trans Union at (800) 888-4213.

You may also check out their Web sites. Click on experian.com, transunion.com and equifax.com. You may even be entitled to a free report.