Sadly, a recent report from the U.S. Department of Health and Human Services inspector general found that 18% of claims that they examined were denied which actually should have been covered. The denials were often a result of errors in processing claims. The review also found that the plans turned down 13% of authorizations for medical services that government-run Medicare would have allowed. The results of the study covered 15 of the largest Medicare Advantage plans in the nation. The investigators said the Medicare Advantage plans use the same tactics that private insurance companies use to get out of paying legitimate claims in order to reduce costs. The report recommends more government oversight of the plans.