Unions usually advance employees based on:

Unions primarily advance employees based on seniority, which refers to the length of time an employee has worked in a particular organization or position. This approach is rooted in the belief that those who have served longer are deserving of advancements, promotions, and benefits over newcomers or those with less experience in the company. This principle aims to provide a fair and structured progression within the workforce, minimizing biases that may arise from evaluating other factors such as age, skill, or merit.

In many union agreements, seniority often plays a crucial role in job security, layoffs, and promotions, ensuring that employees are treated equitably and rewarded for their long-term commitment to the organization. This method of advancement is particularly common in industries with strong union representation, where collective bargaining agreements highlight the importance of seniority in workplace decisions.