"We understand that our work stoppage has created disruption and uncertainty in the lives of your children and families," it read. "Please trust that we are doing everything we can to encourage a speedy conclusion to our contract talks."
The decision by the union's delegates, a body that has the exclusive authority to cease or extend a strike, was a jolting development after Lewis said Sept. 14 that she was "very comfortable" with the terms of a teacher-evaluation procedure that was a key point of contention. She said the language probably would "assuage" the concerns of union members.
The delegates thought otherwise, and Lewis backtracked after the meeting Sunday at a South Side union hall.
"This is not a good deal by any stretch of the imagination," she said.
Chicago Public Schools issued details of the contract about 90 minutes before the delegates voted. The proposed three-year contract with an option for a fourth states that "student growth" will account for 25 percent of a teacher's evaluation in the first two years of the pact, and 30 percent in the third.
A "student survey will be piloted" in the second year and would contribute to 10 percent of the teacher evaluation, the school system said. The contract would provide a 16 percent pay increase over the four years.
The contract carries a price tag of about $74 million for each year, for a total of $295 million over four years. The district faces a 2013 budget deficit of $1 billion.
The strike has been the most public show of resistance to Emanuel since the former chief of staff to Democratic President Barack Obama took office 16 months ago with a pledge to restructure the city's operations. Lowering labor costs is central to Emanuel's initiatives.
The teachers struck for the first time in 25 years after negotiating with the mayor since November over his efforts to lengthen the school day and year, as well as his school board's decision to cancel a 4 percent pay increase. In 1987, union members walked out for four weeks.