n Teacher evaluations: The union is particularly concerned about a new teacher evaluation system, arguing it would be unfair because it would rely too heavily on students’ standardized test scores and 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.

n 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. Mayor Rahm Emanuel said Monday the two sides disagree over who should decide which teachers get hired back. The district has offered jobs to teachers at other schools if theirs close, if there are openings, while offering to put them in a reassigned teacher pool for five months or give them a three-month severance package.

n 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 a “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. The average salary of a Chicago public school teacher is $76,000, according to a district spokeswoman.