Borrowers Beware: You Only Think You Know Your Credit Score.

NEW YORK (TheStreet) -- You'd think the credit score you get is the same one a creditor gets.

You know, the company that makes an up-or-down decision on whether you get that new home, car or loan to open a small business.

Inconsequential stuff like that.

But if you thought so, you're probably wrong -- or so says the nation's consumer advocacy agency.

One in five consumers get a different credit score than the one that goes to creditors, the Consumer Financial Protection Bureau says. The CFPB think that's a big deal, since a lender could see a "meaningfully different score."

"This study highlights the complexities consumers face in the credit scoring market," CFPB Director Richard Cordray says. "When consumers buy a credit score, they should be aware that a lender may be using a very different score in making a credit decision."

The CFPB is mandated to study and recommend any needed changes in the relationship between consumers and credit score agencies, and the study is the first major step in that direction for the agency -- a thorough one that included analyzing 200,000 consumer credit files.

Conclusions from the report are not generally helpful to consumers who need to get credit:

Different scores can lead to "consumer harm." With lousy credit score data, consumers may apply for credit "they are not qualified for" or could "accept offers that are worse than they could get" and end up paying higher interest rates in the deal.

Not knowing may be the worst part. With faulty data, consumers "cannot rely" on the credit score they get and as a result "won't understand how lenders view their credit health."

What can consumers do to get the same credit score that lenders get? The agency advises consumers to "shop around" for different loan or credit terms, as not all creditors use the same financial formulas, and to check credit scores on a regular basis looking closely for errors or "inaccuracies." Each nationwide credit bureau is required by law to provide credit reports for free to consumers who request them once every 12 months.

The CFPB began formally monitoring credit agencies and how they create consumer credit scores Sept. 30. But in the end, it's not Uncle Sam's job to make sure you have the same credit score a potential lenders gets or ensure you get the best deal possible from creditors.

That is up to you.