Net Promoter Score (NPS)

Net Promoter Score (NPS) is a standardised customer loyalty metric calculated as the percentage of promoters (scores of 9-10) minus the percentage of detractors (scores of 0-6) on a single likelihood-to-recommend question.

The result is a whole number between -100 and +100. A score of 0 means detractors and promoters are equally represented. A positive score means more promoters than detractors; a negative score means the reverse.

The calculation

The survey asks one question: “How likely are you to recommend [firm/service] to a colleague or peer?” Respondents score on a 0-10 scale. They are then placed into three groups:

• Promoters: scores of 9 or 10. These clients actively advocate for the firm.
• Passives: scores of 7 or 8. Satisfied but not enthusiastic. They are excluded from the calculation.
• Detractors: scores of 0 through 6. Unhappy clients who may share negative impressions.

NPS = % Promoters minus % Detractors.

For example: 60% promoters and 15% detractors gives an NPS of +45. The passive group (25%) does not affect the score but should be tracked separately because passives are convertible.

What NPS measures and what it does not

NPS measures overall relationship sentiment and the propensity to recommend. In professional services, a high NPS correlates with referral likelihood and renewal probability. It does not measure satisfaction with a specific interaction or deliverable; that is the role of Customer Satisfaction Score.

NPS is a lagging indicator at the relationship level. A score taken six months after an engagement reflects the cumulative impression of everything that happened during delivery, not a real-time signal. For real-time signals during delivery, operational metrics such as milestone completion rates and unresolved issue log items are more actionable.

Survey timing in professional services

NPS surveys administered in professional services typically occur at two points: immediately after engagement close-out and at periodic intervals during ongoing relationships. The post-delivery survey captures sentiment while the engagement is fresh and while any value gap is still visible to the client. Periodic relationship surveys, often aligned with an Executive Business Review cycle, track whether sentiment is improving or declining over time.

Surveying too frequently dilutes response rates and trains clients to ignore the instrument. Once per engagement and annually for ongoing accounts is a common standard.

Benchmarks and interpretation

NPS benchmarks vary significantly by industry. Professional services and consulting firms generally see scores in the +30 to +60 range for accounts where delivery met expectations. Scores below 0 signal a relationship in active distress. Scores above +70 are exceptional and typically reflect engagements where the firm materially exceeded the client’s expected outcomes.

Within a firm’s own portfolio, the more useful benchmark is trend over time at the account level. An account that moves from +40 to +10 across two consecutive NPS cycles is a retention risk regardless of how that score compares to an industry average. An account that moves from -10 to +30 is responding to remediation efforts. Absolute scores matter less than direction.

Relationship to net revenue retention

Aggregate NPS across a portfolio of accounts is a forward-looking input into net revenue retention. High-NPS accounts renew and expand; low-NPS accounts contract or churn. Firms that track NPS at the account level and correlate it against subsequent renewal and expansion outcomes build a model that makes NRR more predictable.