Employee Retention Rate is a key business metric used to measure how many employees remain with an organization over a certain period of time. It is used to calculate the average number of years that each employee stays in their role. High employee retention rates indicate that employees are happy and content in their roles, and less likely to leave the organisation or search for a new job elsewhere. Low retention rates suggest issues such as low salary, lack of career advancement opportunities or a hostile work environment. Companies should strive to maintain high employee retention rates, as this is vital for success and could help save valuable resources in recruitment and training costs.