Net Promoter Score is the management equivalent of checking your weight every hour.
The number wobbles for reasons unrelated to underlying health. It produces anxiety without information. It substitutes a single legible number for the actual signal, which is the messy text the respondents wrote next to the number. The score itself tells you nothing actionable.
Three reasons the obsession is harmful, beyond the obvious.
First, NPS averages over the population that responded. The population that responded is not the population you care about. The most valuable customers are too busy to fill out surveys. The most dissatisfied customers have already churned. The middle, who respond, is the noise band where most signal is absent.
Second, the number is a lagging indicator. By the time NPS moves, the cause is months in the past. By the time you investigate, the cause is harder to identify because more variables have moved in the interim. NPS-driven analysis is forensic archaeology dressed up as product feedback.
Third, the number invites comparison. Last quarter's NPS was forty-six. This quarter's is forty-three. Is that meaningful. Almost never. The variance bands on NPS at typical sample sizes are wider than most quarter-over-quarter movements. Treating the three-point change as signal is overreading the data.
What you should do instead.
Read the detractor comments. Every one of them. Out loud, at the team meeting, with no editing. Three weeks of detractor comments will tell you more than a year of NPS scores.
Read the promoter comments. They tell you what the product is actually doing for the people who love it, which is rarely what the marketing thinks it is doing.
Stop tracking the number. The number is summary statistic dressed as a metric. Track the underlying behaviors, retention by cohort, expansion by cohort, time to second purchase, time to feature adoption. Those are real numbers about real things.
Every team I have ever audited that obsessed over NPS was using it as a substitute for the harder work of reading customer feedback. The obsession is a tell. If your team has an NPS dashboard but cannot quote the last three detractor comments from memory, the dashboard is procrastination.