Superintendent Walt Rulffes said that although the district could have notified the schools earlier of the changes, and will do so in the future, parents need to understand that the school system's exceptional growth requires that some elementary schools convert to a year-round calendar.

"This is a community process we go through," Rulffes said. "Year-round schools are here to stay."

Dozens of parents from several elementary schools lobbied the School Board on April 12 about the district's decision to convert their schools to year-round. District officials then decided to re-evaluate whether the 11 schools recommended for the change met the district's rule that requires them to convert to a 12-month calendar.

Parents from five Henderson elementary schools -- David Cox, Gibson, Galloway, Twitchell and Vanderburg -- held community meetings with district officials after the School Board meeting to object to the district's April 1 decision.

Only Gibson and David Cox were spared Monday from going to year-round in the fall. District officials said the enrollments at the two schools in kindergarten through third grades were declining.

That decision left at least one Twitchell parent dumbfounded.

Brooks Whitmore, who has a daughter in second grade and a son in fourth grade at the school, said at the news conference that the district's decision will cause teachers at Twitchell and nearby Vanderburg to transfer to schools that are nine-month.

"Those are the number one and number two performing schools in the Clark County," Whitmore said. "They are about to disrupt that."

District officials said Vanderburg and Twitchell met federal No Child Left Behind Act standards last school year but under the same standards were not among the district's 19 highest-performing campuses.

District officials repeatedly said Monday that they do not have any evidence that students in year-round schools perform worse academically than students at nine-month schools.

"We don't have any significant data to show there is any difference," in school performance, Rulffes said.

Eighty-five of the district's 199 elementary schools are year-round. District officials also announced Monday that 13 elementary schools will convert from a year-round calendar to a nine-month calendar in the fall because of decreasing enrollments.

The district will build new schools under its current bond until 2010. A total of 101 new campuses will be built by then, said Leah Marchione, a spokeswoman with the district.

She added that school system officials are expected to solidify plans for the next bond that will be brought before voters in November 2008 by spring of that year.