A project labor agreement, or PLA, is a binding contract between a government or private entity that needs a construction project done and a labor union. Before workers are even hired on a project, the two sides negotiate a PLA that sets wages, benefits, work conditions and often provisions for resolving labor disputes to prevent strikes or other work stoppages.

In Illinois – a state with historical ties to the labor movement and a government dominated by labor-friendly Democrats – PLAs have long been a tool that has kept union participation rates high in the construction industry.

Non-union industry groups and conservative organizations have long criticized the practice of governments using, encouraging or mandating PLAs, arguing that forcing projects to use union labor makes them slower and more expensive. But new research from the Illinois Economic Policy Institute and the University of Illinois’ Project for Middle Class Renewal found the opposite.

The study, commissioned by the state’s Capital Development Board, found that PLAs in Illinois have enhanced bid competition, helped to lower construction costs for taxpayers and increased business for firms owned by people of color, women and veterans.