Should a large, long-running state program, vital to the security of Hawai'i and costing hundreds of millions of taxpayers' money, be subject to at least one thorough, independent audit?

The answer is obvious: Yes. That's why lawmakers have advanced Senate Bill 2342, which calls for the state auditor to examine the performance of the largest of the private Mainland prisons that house more than 2,000 of Hawai'i's inmates.

It's a sensible idea. And with the program in its 12th year, it's about time.

In 1996, the state sent 300 prison inmates to the Mainland in a temporary effort to ease overcrowding in Hawai'i's facilities.

Today that effort has become, for all practical purposes, a permanent public policy.

With no firm plans to bring the inmates home, Hawai'i taxpayers will continue to pay more than $50 million a year to send inmates to the Mainland. It may be the only solution, but it's not a good one.

Experts agree that keeping prisoners far from home and the support of family increases the risk of recidivism. And persistent reports of gang-related violence and drug trafficking in the prisons raise fears that inmates will bring this gang culture to Hawai'i's streets when they get home.

That's why it's critical that we know the preventive programs the state is paying for — including mental health services, substance abuse treatment, education and vocational training and proper visitor procedures — are managed effectively by the contractor, Corrections Corporation of America.

CCA and the state Department of Public Safety argue that an independent audit is unnecessary. Public Safety already conducts quarterly audits, they say, and conducts on-site visits by its experts.

There's no reason to doubt the sincerity of Public Safety's position, or its good faith in managing its prison contracts. But a thorough, unbiased audit must examine the quality of the information we're getting now: in other words, the adequacy of Public Safety's oversight as reflected in its audit reports, which consist of a checklist, plus room for short comments. An independent auditor, not the department itself, should decide if these reports are adequate.

The proposed audit would cover CCA's Saguaro Correctional Facility in Eloy, Ariz., which houses about 1,800 male prisoners. It's unfortunate the other two facilities — the Otter Creek women's prison in Kentucky and the Red Rock facility for men in Eloy — are not included because of worries about the cost.

But even so, this prison audit, expected to cost $150,000 or more, is a worthwhile investment in open, informed government.