CSAT asks one question right after a contact — "How satisfied were you?" — usually on a 1-5 or 1-3 scale, and reports the percentage of responses that land in the top one or two boxes.
The formula is deceptively simple: positive responses divided by total responses, times 100. The trouble is what sits underneath it.
What it hides: response rates are often in the low single digits, and the people who bother to answer skew to the delighted and the furious. A rising CSAT can mean better service or simply that your quiet, mildly-annoyed majority stopped replying. Read it next to response rate, or it flatters you.