Collective bargaining is exercised by unions to gain better pay and working conditions for their members. The process of collective bargaining involves representatives from management and from workers' organizations attempting to reach mutually agreeable solutions between the two groups. When this process breaks down, the result is often a strike or work stoppage.
The process of collective bargaining allows an ongoing relationship between labor and management to develop. Policies and standards are put into place so that each side knows what to expect from the other. This dynamic decreases the risk of disruption to the work environment when one side or the other makes an unexpected move or demand. Even when the two sides are at odds or in disagreement, it is helpful for everyone to know the context of the conflict and to understand the position of each side. Collective bargaining increases ongoing communications between all parties.
Workers who work without a union are subject to the dictates of the employer. In a large workplace, a single employee has little power. This is particularly true in periods of high unemployment, when a worker has no leverage because she could easily be replaced by someone else who would do the job without complaint. Collective bargaining through a union effectively transforms a group of atomized workers into one large worker with whom management has no choice but to negotiate. While management may not be challenged by the loss of one worker, it can't afford to lose an entire workforce.
Among the negative effects of collective bargaining is that workers who are employed in unionized workplaces have to pay dues to the union, which are taken out of every paycheck. Over time, this can amount to a substantial sum of money. Different workers have different opinions about this. For workers who are happy with their work situation and don't feel the need for collective bargaining through the mediation of a union, the requirement to pay union dues can seem onerous and unnecessary.
Union decisions during the process of collective bargaining are decided by vote. In large unions with thousands of members, there are inevitably a lot of people who don't get their way when it comes to a vote. This can be a problem for someone who is a member of a union, is represented in the process of collective bargaining by the union, but who doesn't agree with union policies or decisions. Being consistently outvoted by a majority can leave individuals alienated and effectively unrepresented.