One federal official has shot down Charleston County School District's attempt to delay implementing a controversial new teacher evaluation system.

District leaders had asked for an extra year to phase in the new BRIDGE evaluation system, which would've meant all of the district's teachers wouldn't be subject to the new evaluations until the 2016-17 school year.

"After reviewing the timeline and rationale you provided . we do not believe that CCSD has sufficient rationale to approve your request," wrote Michelle Padilla, an education program specialist for the U.S. Department of Education in a letter to the district.

District leaders aren't giving up, and they don't consider this answer final. School Superintendent Nancy McGinley declined to comment via district spokesman Jason Sakran, who said the district still was in communication with federal officials and wanted to wait until further clarification could be obtained.

School Board Chairwoman Cindy Bohn Coats said the board supports the district's effort to push back the roll out of the BRIDGE evaluation system. If the superintendent can't get the answer she wants, Coats said the board would have an open discussion about its next steps.

The district needs federal officials' permission for the delay because the federal government gave the district the $23.7 million Teacher Incentive Fund grant to develop and implement BRIDGE, which is the new evaluation and compensation systems.

The evaluations are being pilot-tested in 14 schools this year, and the district promised in its grant application to expand the evaluation in 2014-15 to all teachers in BRIDGE schools, as well as to core academic subject teachers in grades 4-8 across the district.

Padilla pointed out in her letter that the application required a timeline, and the district was approved based on its assurance that it would meet the grant's requirements, including that timeline.

McGinley said earlier this week that she wasn't inclined to move forward with any district-wide evaluation system until she had more confidence in it than she does right now.

Patrick Hayes, a third grade teacher who leads the education advocacy group EdFirstSC, said he didn't see how the district could stick to its proposed timeline when officials have indicated they aren't where they need to be.

"It seems to me that the path forward is clear," he said. "It's time to let go of the grant."

The new evaluation has three components - students' growth, classroom observations, and teachers' evaluations on the state ADEPT system - and the most controversial of those are students' growth as measured by test scores, or value added. Value added is a formula that will compare what a student's test scores would have been for an average teacher compared to his actual teacher.

Padilla's letter to the district indicated that it might have some flexibility around value added, and she mentioned that in a paragraph that referred to high school teachers.

The district had proposed using student learning objectives, or an alternative way of measuring students' progress that doesn't involve standardized tests but does use objective goals, instead of value added for teachers at the secondary level in 2014-15.

"Although the timeline for implementing CCSD's district-wide evaluation system for all educators cannot change, we believe that the use of (student learning objectives) in lieu of (value added measures) would be an acceptable alternative until CCSD is able to transition . to value added ." Padilla wrote of that request.

McGinley told teachers in a memo that the district was looking for clarification about that flexibility and what it might imply. They haven't received an answer yet.

Reach Diette Courrégé Casey at @Diette on Twitter or (843) 937-5546.