"It's a less optimistic estimate today," says Harry Ballantyne, who was chief actuary until 2001.

In 1945 he was appointed chief actuary of the Central house of social insurance.

Stephen Goss, chief actuary for the Social Security program, defended the administration's assumptions.

Federal law says the chief actuary "may be removed only for cause."

Roland E. King, chief actuary of the Medicare program from 1978 to 1994, voiced similar doubts.

As chief actuary, Mr. North would head a department of 42 employees, managing pension systems whose combined funds amount to $35 billion.

The salary of $175,000 a year makes the chief actuary the second highest-paid city official, surpassing the Mayor, whose salary is $130,000.

A loophole in the law lets non-actuaries serve as chief actuaries at Medicare, Social Security and other agencies.

Federal law says the chief actuary shall follow "professional standards of actuarial independence" and can be removed from his job "only for cause."

When the search committee began its work, Mr. Crowder recalled, the city was still trying to find a chief actuary for around $100,000 a year.