Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington, recently announced that she was leaving the watchdog group to practice law with former Clinton White House counsel Lanny Davis.

Her move may not be entirely for financial reasons, since she makes a handsome salary among her nonprofit peers. But in private practice, she could easily quadruple her earnings.

According to CREW’s most recent IRS filing, Sloan is paid more than $230,000 a year to run the group, which describes itself as an “organization dedicated to promoting ethics and accountability in government and public life by targeting government officials — regardless of party affiliation — who sacrifice the common good to special interests,” according to the group’s website.

In an e-mail Friday, Sloan wrote that her salary is set by the organization’s board, which “bases it on CREW’s effectiveness.” The group’s board in recent weeks undoubtedly had reasons to be delighted with Sloan, who has been a persistent antagonist of former Ways and Means Chairman Charlie Rangel (D-N.Y.) and ex-House Majority Leader Tom
DeLay (R-Texas).

On Thursday, the House voted 333-79 to censure the Empire State Democrat, the first time in more than 25 years the chamber has done so. And a Texas jury on Nov. 24 convicted DeLay of money laundering and other infractions, crimes that could put him in prison for 20 years.

A review of the recent tax filings for other organizations shows that Sloan is paid considerably more than her peers at similar Washington, D.C.-based watchdogs such as the Campaign Legal Center, the Center for Responsive Politics, Democracy 21 and Public Citizen.

The next highest-paid executive, Campaign Legal Center Executive Director J. Gerald Hebert, makes $185,000, or about 20 percent less than Sloan.

Sloan started CREW after leaving the Justice Department in 2003. According to her official biography, she’s also worked in private legal practice and is a graduate of the University of Chicago law school. She is a former assistant U.S. attorney in the District of Columbia and ex-staffer to House Judiciary Chairman John Conyers (Mich.), Senate Rules and Administration Chairman Charles Schumer (N.Y.) and Vice President Joseph Biden during Biden’s Senate days.

“I’m sure they’re considering her career as a prosecutor and what she could make in the private realm,” a source from the downtown nonprofit community said.

Sloan took issue with any suggestion that her salary may be inflated. In an e-mail, she wrote that Trevor Potter, a Republican election lawyer and Campaign Legal Center president, actually makes more because he’s paid $120,000 to work 15 hours a week, according to IRS tax forms.

“Based on that ratio, it seems he is paid more than I am,” Sloan wrote.

Using Sloan’s argument, Potter would make about $320,000 per year for an equivalent 40-hour work week.

In an e-mail, Potter declined to comment.

The head of Public Citizen, an elder statesman among watchdog groups, is also paid considerably less than Sloan. In 2009, Robert Weissman took over from longtime Public Citizen head Joan Claybrook and, although his tenure is too short to appear in tax forms, an organization spokesman disclosed Friday that he is paid $157,000 a year.

“It’s the low end of the range of comparably sized organizations,” the spokesman said.

IRS tax forms also show that Fred Wertheimer, president of Democracy 21, is paid less than Sloan. According to his official biography, the former Common Cause president has decades of experience and is a graduate of the University of Michigan and Harvard Law School.

Wertheimer makes $113,300 annually, less than half of Sloan’s overall pay, tax forms reveal.

Wertheimer declined to comment.

An executive recruiter interviewed for this article said it’s not uncommon for salaries to vary so dramatically within even such a narrowly focused industry. For many top jobs, the source said, “the No. 1 factor … is what you’re making now.”

“Believe or not, employers take into account what you’re making now in figuring out your salary, so most of the time they see what you’re being paid now and can certainly pay in and around that,” the source said.

Executive compensation at nonprofit groups also may also hinge on who pays the organization’s bill, the source said.

“You have to look at A) who funds it, and B) who are they really?” the recruiter said. “What are they doing and who backs them?”

That information is not typically made public on tax forms.