About four months into a bumpy first year, a privately run alternative school on the North Side has lost its principal.

Rick Sternberg resigned from the Community Education Partners school Dec. 31, and Georgia Vassilakis was named principal, at least for the time being, CEP Chief Executive Officer Randle Richardson said.

Mr. Richardson said he didn't expect Mr. Sternberg, a retired Pittsburgh Public Schools principal, to be a long-term employee but believed he would stay through the end of the school year.

"Rick did what he committed to do, which was to come and establish the program," then told Community Partners last fall that the job was too consuming, Mr. Richardson said.

Mr. Sternberg, former principal of Pittsburgh Grandview K-5 and president of Pittsburgh Administrators Association, couldn't be reached.

The Pittsburgh school board agreed to pay the company $5.7 million annually for six years to run the school in the former Clayton Elementary building.

Pittsburgh Public Schools principals refer chronically disruptive students to the school, which provides instruction and other services for about 180 days with the goal of returning them to their home schools.

Ms. Vassilakis had been working as Community Partners' liaison with the district and agreed to take over as principal, though Mr. Richardson said it's too soon to say whether she'll have the job permanently.

She is former principal of a district-run alternative education program, and J. Kaye Cupples, the district's executive director of support services, called her a good choice to take the helm. He also said he believed Community Partners intended to conduct a national search for Mr. Sternberg's permanent replacement.

Called Clayton Academy, the school has an enrollment of about 300, and the district plans to add 100 more students in coming months. The school, for grades six through 12, educates boys and girls separately.

The district still operates its own alternative education programs, but brought in Community Partners, based in Nashville, Tenn., as an additional option.

As might be the case with any new program, CEP's first year has been bumpy, with some students objecting to their placement at the school and complaining about the uniforms they wear and the quality of lunches, Dr. Cupples said. Mr. Richardson said there also were snafus with transportation and other operational issues.

Officials have documented 15 fights among students, three assaults on teachers and two instances of vandalism, but Dr. Cupples said those statistics are better than at some district schools. He said three teachers have quit, two of them because "they didn't like the population."

Community Partners' work in Pittsburgh was opposed by North Side neighbors and viewed with skepticism by some school board members because of the company's controversial track record in other cities. Critics have accused the company of poor performance or not giving districts enough data to assess performance -- complaints rejected by Mr. Richardson.

Dr. Cupples said he doesn't yet have data to show whether Clayton Academy students, often two or more years below grade level, are gaining academically. But he said district schools are reporting calmer learning environments with disruptive students reassigned to the alternative school.