Contract Issues in the Chicago Teachers Strike As Chicago teachers walk the picket lines, their union and the city's school district resumed negotiating a new contract that includes bigger salaries, more benefits, revised job security measures and revamped teacher evaluations. Thursday is the fourth day of the strike. Here is a breakdown of the issues on the table: TEACHER EVALUATIONS: The union is particularly concerned about a new teacher evaluation system, arguing it would be unfair because it relies too heavily on students' standardized test scores and does not take into account external factors that affect performance, including poverty, violence and homelessness. They argue it could result in 6,000 teachers losing their jobs within two years. The district says the union already agreed to the new evaluation system, but it has offered to make adjustments. JOB SECURITY: Worried about dozens of schools that could be closed in the next few years, the union has pushed for a policy to recall laid-off teachers when jobs open up anywhere in the district. The district says that could force principals to hire teachers they don't believe are qualified. Instead, it has said that if a school closes, teachers would have the first right to jobs that match their qualifications at the schools that absorb the children from the closed school. It also offered to put them in a reassigned teacher pool for five months or give them a three-month severance package. SALARY and BENEFITS: The school district has offered a 16 percent raise over four years - double an 8 percent offer made earlier - as well as "modified step increases" that it says reward experience and provide "better incentives for mid-career teachers" to keep them from leaving. The district also wants to do away with the ability of teachers to bank sick days but is offering short-term disability, including paid maternity leave. Chicago teachers are among the highest-paid in the nation. Their average salary is $76,000, according to the school district. LONGER SCHOOL DAY: This central issue appeared to be solved after the two sides agreed weeks ago to a plan allowing the hiring of nearly 500 teachers to cover a longer school day without forcing teachers to work longer. But union officials remain angry about how Emanuel tried to go around them to get the longer day in place early, including offering incentives to individual schools. Union President Karen Lewis has complained about how the longer day is being implemented.