DALLAS (CBSDFW.COM) – More than 250 Dallas ISD teachers won’t be returning to their classrooms next year.

Texas public school educators work under negotiated contracts. The Houston Independent School District has the largest teacher pool tied to year-long agreements.

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Dallas ISD is second. With 10,000 teachers, Dallas ISD invariably faces resignations, removals and retirements.  But this year, Dallas ISD is seeing a spike in teachers having their contracts slashed.  It’s called non-renewal.

“This is about giving our kids the best,” according to Dallas School Board Trustee Mike Morath.  Morath says the district is putting more emphasis on evaluating teacher effectiveness in the classroom.  “There are specific criteria for the evaluations,” he explains.

School principals assess the teachers they’ve hired to educate children.  School district contracts are automatically renewed annually, unless there is specified reason or cause.

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Last school year, Dallas ISD trustees approved 52 non-renewals for poor performance.  So far, this school year’s tally sits at 259.

Morath said the number is small in comparison to the district’s overall teacher population.  “We have one chance with our kids, and every year we don’t give our best is one year they (students) don’t get back”.

Rena Honea, president of Alliance AFT, the largest teacher association for Dallas ISD, voiced concern over the evaluation of teachers. While in New York today, Honea questioned if the non-renewals were genuinely performance-based.  Honea cited growing budget problems for Dallas ISD as a possible motivator for approved non-renewals.

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Teachers facing the poor performance contract cuts can appeal the decisions.