Background: Scott Kevin Walker (born November 2, 1967) is an American politician serving as the 45th and current Governor of Wisconsin since 2011. First elected Wisconsin Governor in the 2010 general election, he won a 2012 recall election and was reelected a second time in 2014. He is a former member of the Wisconsin State Assembly and a former Milwaukee County Executive. Born in Colorado Springs, Colorado, Walker was raised in Iowa and in Delavan, Wisconsin, before attending Marquette University.
Context: On April 2, 2012, Walker signed a law to fund evaluation of the reading skills of kindergartners as part of an initiative to ensure that students are reading at or above grade level by 3rd grade. The law also created a system for evaluating teachers and principals based in part on the performance of their students. It specified that student performance metrics must be based on objective measures, including their performance on standardized tests.  Walker approved a two-year freeze of tuition at the University of Wisconsin System in the 2013 budget. In 2014, he proposed a two-year extension of the freeze based on expected cash balances for the system in excess of $1 billion.  On February 3, 2015, Walker delivered a budget proposal to the Wisconsin Legislature, in which he recommended placing the University of Wisconsin system under the direction of a "private authority", governed by the Board of Regents (all the governor's appointees). The budget proposal called for a 13% reduction in state funding for the university system.  The budget proposal also called for re-writing the Wisconsin Idea, replacing the university's fundamental commitment to the "search for truth" with the goal of workforce readiness. Walker faced broad criticism for the changes and at first blamed the rewriting of the Wisconsin Idea on a "drafting error." Politifact and the Milwaukee Journal Sentinel later reported that Walker's administration had insisted to University of Wisconsin officials on scrapping the Wisconsin Idea, the guiding principle for the state's universities for more than a century. Walker then acknowledged that UW System officials had raised objections about the proposal and had been told the changes were not open to debate.
Question: How were they evaluated?. Whats the answer?
based in part on the performance of their students.