The Net Promoter Score is an index that essentially measures customer loyalty to a product, service, or company. Typically, this number is obtained through a survey that is sent to customers after interaction with a brand.
Three different emails were sent containing the same body text but different subject lines. Here are the headlines and results:
IBM’s e-business Innovation Centre in Toronto ran an online business-to-business survey between 2000 and 2001, and after tweaking a number of variables they managed to double their response rates in the second year of running the survey.