It's the kind of screwup that makes the public nervous about how their tax dollars are spent: Despite a scathing 2009 legislative audit that contributed to a major computer system overhaul, a Minnesota state department continued to pay too much for personal care services.

The Minnesota Department of Human Services covered bills for services based on impossible work hours and charges that violated work-hour limits. According to a May 23 Star Tribune news investigation by Glenn Howatt and Pam Louwagie, since last summer DHS checks were sent at least 21 times when bills claimed that attendants worked more than 24 hours a day. Hundreds of other invoices were paid over the last year even though they exceeded a new 16-hour daily limit that caregivers are allowed to work.

That certainly doesn't inspire faith in government. If reporters found the overpayments with data supplied by DHS, why couldn't the department spot the problems? Department officials should have caught the overbilling, especially since they've been carrying out system reforms for the past several years.

After a January 2009 auditor's review found that the personal care system remained "unacceptably vulnerable to fraud and abuse,'' officials should have put systems in place to prevent this kind of error. The state audit revealed that more than 400 improper payments were made in one month to companies that claimed attendants worked more than 24 hours a day.

Despite the need for tighter controls, the Personal Care Assistance (PCA) program is critical to the state's efforts to reduce health care costs. Aging or disabled people who need help with tasks such as eating, bathing and dressing are eligible for the service that allows them to remain at home instead of going to nursing homes or group homes.

PCA is funded almost equally by the state and federal Medicaid programs. In 2009, nearly 22,000 low-income state residents with disabilities such as autism, cerebral palsy, diabetes and attention deficit disorder received help. Since 2002, PCA expenditures have grown from $153 million to around $500 million.

DHS officials say they corrected the computer problem that caused the errors uncovered by the Star Tribune after reporters brought the problem to their attention. And they said they are in the process of recovering the overpayments, estimated at about $24,000, for those who claimed to work more than 24 hours in a day. Providers that were overpaid will have those amounts deducted from future payments. At least that's the hope and stated goal.

Loren Colman, assistant DHS commissioner, said training for providers and improved computer programs have reduced errors throughout the system. Yet he acknowledged that, "We clearly need to improve our integrity to the payments claims.''

It's admirable that officials are acknowledging the mistakes and are continuing to take steps to correct them. They should move posthaste. Minnesota taxpayers should have complete confidence that their tax dollars aren't being wasted by bureaucratic ineptitude.