Satisfaction, effort, speed, and cost. Each one answers a different question — and they are easy to confuse.
CSAT Customer Satisfaction
A short survey sent right after a contact, asking how satisfied the customer was — usually "rate your experience 1 to 5." CSAT is transactional: it measures how that one interaction felt, while it is fresh. It is the most common support metric, but it is biased toward people who bother to respond, so read it alongside the conversation scores, not instead of them.
Related: CSAT vs. NPS vs. CES
NPS Net Promoter Score
A relationship metric that asks "how likely are you to recommend us?" on a 0–10 scale. Promoters (9–10) minus detractors (0–6) gives a score from -100 to +100. NPS measures loyalty to the whole brand, not a single support contact — so it moves slowly and is a poor way to grade an individual conversation. Useful at the company level, blunt at the ticket level.
Related: CSAT vs. NPS vs. CES
CES Customer Effort Score
How hard the customer had to work to get their problem solved, usually phrased as "the company made it easy to handle my issue — agree or disagree." Effort is the metric that best predicts loyalty: customers rarely reward you for going above and beyond, but they punish you for making things hard. Lowering effort — fewer repeats, fewer handoffs, no re-explaining — is often the highest-leverage thing a support team can do.
Related: Reduce customer effort
FCR First Contact Resolution
The share of issues solved in a single interaction, with no callback, no follow-up email, no second ticket. FCR is one of the strongest drivers of satisfaction — customers hate repeating themselves — and a good proxy for whether your team has the data and authority to actually fix things on the first try. Measure it honestly against reopen rate so a closed ticket is not counted as resolved.
Related: First contact resolution, explained
AHT Average Handle Time
The average time to handle one contact end to end — talk or chat time plus after-contact wrap-up. AHT is an efficiency metric, not a quality one, and chasing it alone backfires: rushing customers off the line tanks resolution and satisfaction. The right move is to cut the time the work actually takes — better context, fewer lookups, AI drafting the reply — not to rush the customer.
Related: The tradeoffs of average handle time
SLA Service Level Agreement
A promise to respond to, or resolve, a contact within a set time — for example, "first reply within one hour" or "resolution within 24 hours." SLAs set the customer's expectation and the team's target, and are often tiered by channel or plan. Set them where you can actually hit them; a missed SLA is worse than an honest, slightly longer one.
Related: Setting achievable SLAs
Cost to serve
The fully-loaded cost of resolving one conversation: agent time, tooling, overhead, and now AI usage, divided across the conversations you handle. It is the metric that turns support quality into a business case — when an AI agent resolves the routine surge, cost to serve drops without quality slipping. Track it per conversation and per channel so you can see where the money actually goes.
Related: Cost to serve per conversation