The Advocacy Index is a customer survey technique developed by VIRTUATel Ltd that is conducted over the telephone.
[1] The technique measures customer loyalty using a 3-point scale and is based on the Net Promoter Score (NPS) methodology developed by Fred Reichheld.
As they had experience in the area of automated customer surveys, VIRTUATel incorporated the Net Promoter survey technique for driving up-sell, cross-sell and customer retention rates but simplified the 0 to 10 score to use a simple 3 option scale to determine if the survey recipient was an Advocate, Neutral or a Non-Advocate.
[3] This in turn, builds on extensive research in the US by Frederick F Reichheld, consultant to Bain & Co., who created the Net Promoter Score (NPS) methodology.
The research found that both word of mouth advocacy (as measured by net-promoter score) and negative word of mouth were statistically significant predictors of annual 2003-2004 sales growth:[4] The report concludes by suggesting that asking a simple question; "Would you recommend this company?"