Denver's performance-pay system for teachers has long been hailed as a model, in good part because it was jointly conceived and implemented by the school district and the local teachers' union. However, that collaborative spirit is now in jeopardy, with union and district leaders engaged in a protracted battle over proposed changes to the system.…

Leaders in a handful of school districts are pondering the idea of "front-loading" teacher compensation by paying novices more than they would typically earn under traditional salary schedules. Boosting new teachers' salaries, officials in Denver, the District of Columbia, and New York City contend, would increase the applicant pool and…