Few, if any, Minneapolis teachers remain in the ranks from the last time their union struck the school district 42 years ago.That 1970 strike, illegal at the time, led to Minnesota's modern-era law governing public employee negotiations.With Chicago teachers striking for the first time in 25 years, it's important to look at how the situation in Minneapolis differs.Many commentators have painted the Windy City's standoff as Armageddon in the fight between unionized big-city teachers and education reformers supported by conservative interests.But there are important differences in the two districts lying some 400 miles apart.One key element is the Chicago's mayor's control over the system. New Mayor Rahm Emanuel appoints the Chicago school board and its top executive. He's been a point person for management's side. That means leadership operates in a different political environment than Minneapolis, where the union plays a key role in who gets elected to the board. A House Republican proposal last session would have allowed Mayor R.T. Rybak to appoint the Minneapolis board and chief executive, something the mayor said he was willing to discuss, but went nowhere in the Republican-controlled Senate. Rybak has said he sees value in appointing a board with a broader background than simply those who can pass muster at the DFL convention. Another key difference is the degree to which charters have made inroads. The Chicago Public School web site lists around 60 charter schools under the district umbrella. Teachers there say they're concerned about job security because district-operated schools are closing and opening as charter schools. The Minneapolis district authorizes five charter schools, two of which just opened. That's fewer than the number it oversaw 10 years ago as a charter sponsor. There are 30 additional charters in Minneapolis that operate outside the district, but their enrollment growth has essentially flatlined in recent years. Some local charter advocates are urging that low-performing charters shut down, even while advocating that high-scoring charters expand. That's a different climate than Chicago.Another important difference is in how Minneapolis and Chicago and their respective states have implemented teacher evaluation. Both states have mandated evaluations. Minnesota's law passed in 2011 with support from Education Minnesota, the parent group for local teacher unions. The law gives schools districts and unions the power to negotiate their own contract language on what teacher evaluation looks like, within certain parameters. If there's no agreement, districts will follow a statewide model that's still being developed. It must be used starting in 2014-2015, giving three years for the details to be ironed out.The Illinois mandate passed in 2010, and Chicago has been an early adopter. It requires 40 percent of a teacher's evaluation eventually to be based on student test scores. That's more than Minnesota's 35 percent, which can be based on standardized tests or other measures. A letter signed by researchers at 16 local universities warned Emanuel against implementing a system based on standardized tests. They urged him to minimize the amount that student growth counts in an evaluation. Their letter said measuring teacher effectiveness by student test results is like using a yardstick to measure a person's weight.More than 900 Minneapolis teachers got preliminary evaluations last year while the district's system was still in pilot status. It goes district-wide this year. The prime measurement yard stick will be several observations of the teacher, bracketed by a pre and post-conference at which there's discussion between teacher and evaluator. The scale of the district's effort is revealed by the estimated $3.5 million initial annual cost, a figure that's expected to decline somewhat. It is based on standards of effective instruction that have been part of the Minneapolis contract for years. The standards for being approved as an evaluator are tough enough that only a small percentage of principals trained in the observation protocol were fully proficient in their first test.There's a range of reaction on the teacher side. Speaking for her members Lynn Nordgren, president of the Minneapolis Federation of Teachers, described the evaluation system as a work in progress with bugs yet to be addressed. For example, she posed, how does an Anglophone principal evaluate an advanced French lesson? Or how does a math avoider evaluate a calculus lesson?David Heistad, the research director who moved recently from Minneapolis to the Bloomington district, sits on a group that's developing a model for the state's approach to the portion of evaluations based on standardized tests. He's confident that by focusing on growth data, and comparing academic growth in students against their peers who started out with similar demographic characteristics, a fair measurement can be developed for how students in a class progress. But only a minority of teachers teach in areas where there are standardized statewide tests.Rob Panning-Miller, who represents a more militant brand of unionism than Nordgren and was her predecessor as union chief, takes a hard line on the Chicago struggle. That city is much further down the road than Minneapolis to toward what some view as reforms but he views as anathema.In his opinion, the free market is fine for buying a car, but trying to push education in that direction by making charter and district schools competitors undermines what should be a universal right. For example, charter schools typically serve many fewer special education students than district schools, and Minnesota School of Science, a North Side charter school, this summer kicked out a group of special ed students who were co-located in the school and for whom the charter had provided mainstreaming class time.Looking to Chicago, he added: "These reforms, if they're successful, they're going to try to implement them elsewhere. It's sort of like in Wisconsin." They're supported by Democratic President Barack Obama and having Mark Dayton as governor has stopped them here, Panning-Miller said. "This is a reflection of the level of corporate influence in both parties."