The Star Tribune called the 39 districts that have participated in the Q Comp program, passed by the Legislature in 2005, for at least a year. Representatives of 22 of the districts were interviewed.

Some districts -- such as Roseville -- only have some schools participating in the program. For our statistic noting that more than 99 percent of teachers advanced in the professional pay scale, we only counted teachers in participating schools.

In Minneapolis, eight of the district's schools participated in Q Comp's teacher training and bonus programs, but none participated in the Q Comp merit pay scale because the district uses an alternative system. So the district was not included in the teacher pay analysis.

For test score data, the percentages of students reaching proficiency in Q Comp schools were compared with percentages of students in non-Q Comp schools over three years. The participating Minneapolis schools were included. Only data from schools in at least their third year of the program were examined. Only public school districts were analyzed. Charter schools were not.