FULL ANSWER
In addition to providing them with safer, cleaner and more comfortable working environments, labor union advocates support those unions on the grounds that they provide job security and gaurentee a solid, fixed income. They also contend that with the ability to collectively bargain, workers can demand higher wages, more benefits and other perks, such as improved health care and personal time. They also content that unions alleviate managers from the burden of addressing grievances and complaints of workers on an individual basis, which would take away valuable time from production and management responsibilities. Opponents of unions, however, contend that they often prevent more qualified workers from getting jobs and allow less productive workers to remain employed. They argue that on a large scale, unions reduce economic efficiency and make countries’ markets less competitive.