Have you ever wondered why you never heard from a potential employer even though your interview went well and you seem perfectly qualified for the job? It could be your credit history wasn't good enough.

So far four states have passed laws to limit the practice of using a job candidate's credit history in the hiring process and similar bills have been introduced in 20 other states and Congress.

According to The Wall Street Journal, the issue took on heightened interest when the recession left many unemployed workers with tattered credit. The concern being debated is that poor credit could become a barrier to landing a job. Meanwhile, the employers who use this practice say credit checks help them evaluate candidates and protect against fraud.

Another concern is the potential discriminatory impact on hiring. That prompted the Equal Employment Opportunity Commission to hold a hearing this week.

Opponents of the practice cite studies showing that African-Americans and Latinos tend to have lower credit scores. They also dispute whether credit reports are an accurate way to measure an employee's qualifications. One study showed that bad credit was a poor predictor of job performance.

State laws aimed at limiting the use of credit checks tend to carve out exceptions for certain industries. Oregon's law, for example, exempts federally insured banks and credit unions, as well as some jobs in other industries. In Illinois, debt collectors, insurance agents and some state and local government agencies are among those exempt.

Proponents of credit checks, which include fraud examiners and credit-reporting groups as well as employers, contend the histories are an important screening tool for employers and tend to be used sparingly. A recent Society for Human Resource Management study showed 60% of employers used credit checks to vet job candidates.

Michael Eastman is an executive director at the U.S. Chamber of Commerce. He told the EEOC that employers take individuals' circumstances into account. Many at the hearing stressed that employers look for a pattern of careless financial behavior, not one-time events.

According to the Journal, supporters claim credit checks can also be used as a tool to protect businesses against fraud by people who are in debt and have trouble paying their bills on time.

One problem in evaluating credit checks is confusion over what information is included in credit reports, how employers use them and what research has been conducted on the effects of using the checks in employment.

Experian Information Solutions Inc., a company that provides credit reports, offers an employment report that includes details such as a credit history, evidence of bankruptcy or liens, and information on previous employers. What it doesn't include is a person's credit score. It is that which takes into account various details of a person's credit history and synthesizes them into one number. Much of the research on disparities in credit histories between racial groups is based on credit scores, though most employers never see that number.