Staff Advocacy Score is a measure of the extent to which employees are advocates of the business. It can be measured by asking a simple question: "How likely is it that you would recommend this company as an employer to a friend?"
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.