The authors examined 46 Norwegian companies’ data from 2008 in the banking, insurance, utilities, and telecom industries. They used the standard NPS item (0 to 10), a single five-point satisfaction item, top-box satisfaction, a five-item satisfaction index, and a four-item loyalty intention measure. They also included an alternative NPS that used 8–10 for promoters and 0–5 for detractors because “Dutch respondents may give lower evaluations than US respondents (an 8 is already a high grade in the Netherlands).”
They found that all customer metrics (except loyalty intentions) are significantly related to sales growth in 2008 and two-year sales growth over 2008 and 2009. These metrics predicted the outcome measures equally well. They did not report the correlations within each of the industries, but we found in our earlier analysis that satisfaction and NPS correlate strongly or not at all depending on the industry and time period.
Takeaway: They found that the NPS predicted future growth metrics (corroborating our findings and Reichheld’s claim), but both versions of the NPS weren’t statistically different than other metrics. They concluded “there is no single best metric.”