Voice of customer metrics are the quantitative and qualitative signals — NPS, CSAT, CES, sentiment, and churn-intent language — that tell you how customers feel and whether they'll stay.

Voice of customer metrics fall into two tiers: quantitative scores (NPS, CSAT, CES) that tell you what customers feel, and signal-based depth metrics (sentiment, theme frequency, churn-intent language, the "why" behind the number) that tell you why.