WASHINGTON — The Obama administration said Friday that it is considering a college-rating system that would measure whether graduates earn enough money after leaving school to be substantially above the poverty level.

In response to those who worry that ratings could be skewed in favor of colleges with many graduates who strike it rich, the Education Department is weighing a proposal to set an earnings benchmark for recent graduates and former students that it calls “substantial employment.” That could be 200 percent of the poverty level or a multiple of the full-time minimum wage projected over a year, the department said.

Coupled with analysis of longer-term earnings after former students have enough time to settle into a career, the department said, that information could be a basis for rating a school’s “labor market success.”

Ted Mitchell, undersecretary of education, told reporters in a conference call that the department is trying to figure out whether former students are able to “pay their bills, pay their student loans and begin to get on in life” soon after they leave school. “We’re not out to measure colleges that make people rich,” he said.

The federal government collects earnings data through the Internal Revenue Service and the Social Security Administration. But Mitchell declined to pinpoint the source of the data that would be used for ratings. “That’s a work in progress,” he said.

Many details of the plan – from the metrics to the formulas that would tie them together – remain undetermined. But an Education Department document released Friday provides the most comprehensive view yet of the development of an initiative that President Obama announced in August 2013. Plans call for ratings based on measures of access, affordability and outcomes to be published ahead of the next school year.

On Friday, senior congressional Republicans sharply criticized the initiative. “This so-called college-ratings system is a fool’s errand, and the secretary needs to stop it immediately,” said Rep. John Kline, R-Minn., chairman of the House Education and the Workforce Committee, referring to Education Secretary Arne Duncan.

“I can’t support letting Washington bureaucrats use taxpayer dollars to fund a higher education popularity contest,” said Sen. Lamar Alexander, R-Tenn., incoming chairman of the Senate Committee on Health, Education, Labor and Pensions.

The administration maintains that the ratings initiative does not require congressional approval.

Under the plan, there would be no numerical ranking, in contrast to the “top college” lists favored by U.S. News & World Report and others. Instead, the government would issue evaluations such as “high performer,” “low performer” or “in the middle.” Still unsettled is whether schools would receive an overall rating or multiple ratings, or both.