Since our initial deployment of the Net Promoter Score (NPS) for variable compensation at my Professional Services Organization (PSO) two years ago, there are five lessons learned that are broadly applicable for other PSOs that are considering adding NPS to the mix. We chose to deploy NPS because consultants can strongly influence the outcome and benefit from the results. NPS measures whether or not your consultants are creating advocates or adversaries for your brand, which is critical to landing add-on sales at existing clients as well as new customers.