U.S. President Barack Obama speaks at Rhode Island College in October. The Obama administration is expected to release its college ranking system by the end of theweek. Reuters

The White House's contentious and long-awaited college ratings system could be released by the end of the week, according to media reports. President Barack Obama's plan to link federal financial aid to schools' performance isn't due to be in place until the 2015 school year, which starts in August, but its guidelines are expected to be made public this month.

The metrics will revolve around three themes: access, affordability and outcomes, according to the U.S. Department of Education website. Specifics are unclear, but the federal government is expected to evaluate factors like loan debt, graduation rates, alumni earnings and how many students receive Pell grants.

Obama announced the rating system in August 2013 in an effort to hold the nation's roughly 7,000 colleges accountable for their students' success. Since then, several politicians and university administrators have come out against what they see as government overreach. Higher education institutions receive about $150 billion in federal aid each year, the New York Times reported.

“So much of what a college or university offers cannot be captured in a rating system,” Emory University provost Claire Sterk told USA Today earlier this year. “Certainly financial factors need to be considered, but individual students also need to consider … the best possible academic experience that will support their goals and aspirations.”

In the past, college rankings done by companies like U.S. News & World Report, the Princeton Review and Barron's have been widely criticized for their formulas and nature. "Can colleges be ranked at all?" College Confidential asked on its website.

"A lot of colleges and universities say if you start ranking just based on cost and employability, et cetera, you’re missing the essence of higher education and so forth,” Obama said in a Tumblr Q-and-A this summer. “What we’re really trying to do is just to identify: Here are some good bargains; here are some really bad deals. Then there’s going to be a bunch of schools in the middle that there’s not going to be a huge amount of differentiation.”

Unlike private rankings, Obama's system won't assign number values to institutions. Instead, it will give colleges ratings like "excellent," "fair" and "poor."