The close relationship between retention and turnover means the two are often considered together.
Turnover is the proportion of employees leaving an organisation within a set period. High turnover rates can be costly in terms of recruitment, training and loss of knowledge. Calculating the cost of turnover can be useful to understand the scale of the issue and supports the business case for improving retention. The CIPD Turnover and Retention factsheet outlines how to calculate turnover.
When developing retention strategies, organisations are typically more interested in tackling the reasons for voluntary turnover (ie when an employee resigns) than involuntary turnover (eg dismissal due to redundancy), as they have less control over voluntary reasons.