Jim Nobles has spent decades examining state leaders' use of taxpayer dollars and the effectiveness of programs serving those in need.

But 38 years after he was first appointed as Minnesota's legislative auditor, and nearly 50 years after he started his first job in state government as a Minnesota House intern, Nobles is retiring.

His last day is Oct. 5, when he will vacate a position he has filled for most of its existence.

In a letter notifying legislators and colleagues of his retirement, Nobles wrote that he was confident "the good work" of the Office of the Legislative Auditor (OLA) "will continue because of the top-quality professionals who work at OLA, and because of the Legislature's bipartisan commitment to effective legislative oversight and strong government accountability."

During Nobles' lengthy tenure, the Office of the Legislative Auditor has delved into some of the most controversial issues in state government.

Nobles' staff examined the troubled rollouts of the MNsure health insurance exchange and the Minnesota Licensing and Registration System. Auditors delved into the failures of the Metro Gang Strike Force, and more recently, allegations of fraud in the state-subsidized Child Care Assistance Program.

Meanwhile, Nobles has had to walk a political tightrope, holding state leaders accountable while remaining nonpartisan and maintaining the faith of the Legislative Audit Commission.

In response, legislators have repeatedly reappointed him to six-year terms.

The office's reviews of state spending are important, but their audits of programs — such as those serving children and people with disabilities — are particularly critical, said Republican state Sen. Mark Koran, chairman of the Audit Commission.

"The outcomes determine your quality of life and are truly life and death," he said. "So when they do that work, it has to be accurate, it can't be biased and it can't be hindered or burdened with a worry of, 'Does this meet a political view or agenda?' And he's never delivered anything in that manner, even though he's been accused of it."

Sen. Ann Rest, DFL-New Hope, echoed that sentiment. Rest, who served on the Legislative Audit Commission for more than 30 years, said the legislative auditor has extraordinary oversight and accountability responsibilities.

Under Nobles' leadership, Rest said in a statement, "the OLA has done exemplary work in ensuring that state government is working on behalf of Minnesotans, and the office remains independent of political bias even as it thoroughly reviews program areas, financial audits and conducts special reviews."

Nobles did not return repeated requests for comment.

The Legislative Audit Commission will meet soon to accept Nobles' resignation and firm up the process to select the next legislative auditor, Koran said. He expects it will take a few months to appoint the new auditor, and said someone will fill in for Nobles temporarily during the search.

jessie.vanberkel@startribune.com

651-925-5044 • @jessvanb