Amid similar government cutbacks that are happening here in the UK, the tenure of US public sector CIOs is increasingly shorter than their private sector counterparts, a new survey by Gartner finds.

In 2012, the average length of time a local, state or federal CIO in North America (including Canada) stayed in that post was 4.2 years, the same as 2011. But in 2013 that number declined to 3.4 years.

Private sector CIO tenure, by contrast, is nearly a year or more longer than the public sector.

There is no one explanation for the shrinking tenure of public sector CIOs in the US. Last year's election may have played a role, but the federal sequester, salary freezes, and public sector bankruptcies may be responsible as well. Another contributing factor may be CIOs who put off retirement during the downturn, and are now leaving.

Whatever the reasons, Gartner analyst Rick Howard said: "Government CIO tenure is shrinking at a time when dependence on information and data in government is increasing."

Carlos Ramos, the CIO of California, said he recently saw data showing the average tenure for state CIOs at 2.8 years. He says there are several reasons for this.

In some cases a state CIO is appointed at the will of the political office holder. Ramos was appointed by the governor in 2011.

Another reason: The salary levels of public sector CIOs, which are significantly lower than their private sector counterparts. "Public sector CIOs often leverage their credentials to go off into the private sector to make more money," said Ramos.

Public sector CIOs deal with diffuse decision-making, and bureaucratic processes that can be trying, and there is also "little tolerance for failure of an IT initiative in the public sector," said Ramos.

Bill Schrier, the CTO of Seattle for nearly nine years and who now has programme management responsibilities with Washington state's CIO office, sees the public nature of the job and constant exposure to media scrutiny taking a toll on some.

Another stressful issue for public sector CIOs is organisational. Many large government IT organisations aren't consolidated, and have IT shops with their own IT directors and CIOs. "This makes it really hard for the central CIO to succeed because he/she is continually herding cats to get anything done," said Schrier.

But he said tenure may be more stable on the local level. When Seattle changed mayors, Schrier was retained. Most cities and counties are not run by elected executive, but rather by a city or county manager. Those managers often have tenures of a decade or more, and changes in IT management don't come as often, he said.

Gartner's data is based on its annual survey of nearly 2,000 CIOs worldwide, and from all industries. It was taken in the fourth quarter of last year.

The tenure for private sector CIOs in North America was five years in 2011, 4.7 years in 2012, and 3.4 years this year.

Brenda Decker, the CIO of Nebraska and president of the National Association of State Chief Information Officers, said government CIOs aren't taking these jobs for the money, benefits or recognition. "People that take government CIO jobs do it because they have a desire to serve the public and their state," she said.

And with that, they may take that job "with a pre-determined period of time that they are planning to make the commitment to the state," she said.