Employee Satisfaction Index is a multi-item measure of how satisfied employees are. Depending on the organisational priorities, it can include measures such as leadership, career progression, training, company culture, conditions and pay.
This indicator is included in the book: Key Performance Indicators - the 75+ measures every manager needs to know, which contains an in-depth description of this KPI, as well as practical advice on data collection, calculations, target setting, and actual usage.