Tom Prendergast, who previously ran New York’s subway and bus operations, is the new chairman and chief executive officer of New York’s Metropolitan Transportation Authority. But how long will he stay?

Prendergast is the MTA’s fifth head since 2006. In 2009, the chairman and CEO position was established with a fixed six-year term, in the hopes that a long set tenure would allow the MTA’s head to do long-range planning while resisting political influence.

It hasn’t worked as planned. Since 2009, two well-regarded men have taken the role only to leave for greener pastures after about two years. Jay Walder, a seasoned transit executive, left in 2011 to become CEO of the private firm that runs subways in Hong Kong. Joe Lhota, a former investment banker and deputy mayor, quit earlier this year to seek the Republican nomination for New York mayor.

It’s not hard to see why they left. Walder was being paid $350,000 a year -- a salary so high it was considered scandalous, and yet much less than someone qualified to run a $13 billion-a-year operation can make elsewhere. And unlike presidents and governors, it’s hard to say that MTA executives are compensated in prestige: As Lhota’s poll numbers make clear, the public generally doesn’t know who runs the MTA, and if they do, they’re predisposed to think he’s doing a bad job. So Walder left for a job that presumably pays more and Lhota to seek one that would bring greater non-monetary benefits.

The MTA is still in good hands: Prendergast is well-regarded by elites, just as Walder and Lhota were. But since the MTA engages in lots of long-term capital projects, it would be nice to keep the same competent head for several years at a time. We would be more likely to keep Prendergast if we offered him a salary commensurate with the size of the organization he is running and with salaries in the private sector.

In general, we should be willing to pay top government officials very highly. Andrew Cuomo has been criticized for using state helicopters to commute home to Westchester County from Albany, but as a New York taxpayer I’m glad to give him all the helicopter rides he wants. We’re already keeping the governor to a salary of $179,000 -- the least we can do is save him the burden of living in Albany. (As Fred Armisen-as-David Paterson once advised Cuomo, “If you're in Albany, I can recommend a great place to go to dinner. It's called Manhattan.”)

Voters expect a lot from top public officials. We want them to be talented managers who run the government well. We want them to stay in their jobs long enough to see projects to completion. We want them not to be corrupt. And we want them to work for a lot less than they could make elsewhere. Dropping the last goal would make it easier to achieve the first three, which is a reason to give Prendergast a big raise.

(Josh Barro is lead writer for the Ticker. Follow him on Twitter.)