In a report released Friday, the Obama administration offered its first public glimpse of a planned system for rating how well colleges perform, saying it wanted to group schools into three broad categories — good, bad and somewhere between.

In detailing what elements the system is likely to contain, the Department of Education also revealed how dauntingly complex the project has been, and how it continues to be hampered by the limitations of the data available.

The department labeled what the Friday release calls a “draft framework,” much of it subject to change, with a lot of work still to be done before it produces a first version of an actual rating formula. Officials said that first system should become public before the start of the next school year, about eight months away, but even then, it will remain a work in progress, to be upgraded as problems arise and better data become available.

Sixteen months ago, President Obama announced an ambitious system to assess each college on accessibility to lower-income students, affordability, students’ academic progress, and how well the students fare in finding good jobs and paying off student loans. Those ratings could even be tied to the distribution of billions of dollars each year in federal aid, he said.