Four important influences on an employee's decision to join a union are dissatisfaction at work, lack of power, management efforts, and union instrumentality.

These four factors are commonly recognized as important influences on an employee's decision to join a union. Dissatisfaction at work, such as low pay or poor working conditions, can motivate employees to seek the collective bargaining power that a union offers. Employees who feel they lack power in their workplace, either because of their job status or because they are not consulted on important decisions, may also be more inclined to unionize. Management efforts to discourage unionization, such as anti-union campaigns or retaliation against union supporters, can also push employees towards organizing. Finally, union instrumentality refers to an employee's belief that a union will actually be able to make positive changes in their workplace, and this perception can influence their decision to join.