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Glossary · Compliance

What is Complaint rate?

  • Also called: consumer complaint rate, spam report rate

Reviewed by Sujan ThapaliyaLast updated

Definition

Complaint rate is the share of calls or messages that recipients actively report — through a handset's report-spam control, a carrier form, or a regulator. It is a small number with disproportionate consequences, because analytics engines weight it heavily.
The three STIR/SHAKEN attestation levels, which underpin how complaint rate behaves in practice: A asserts both that the carrier knows the customer and that the customer may use the calling number, B asserts the customer only, and C asserts neither. A shared number pool can reach B at best, which is why number ownership keeps recurring in these definitions.
Attestation is the backdrop to most caller-ID and deliverability terms, complaint rate included.

In practice

How complaint rate actually works

Complaints are rare in absolute terms, so a rate that looks negligible can still be the reason a number is labelled. The threshold is not published by any analytics provider, which is why the practical guidance is to treat every complaint as significant.

The strongest predictors of complaints are calling people who did not expect to hear from you, calling repeatedly after no answer, and calling outside reasonable hours.

Because complaints attach to the number rather than the campaign, they persist after the campaign that caused them has ended.

Complaints are also weighted by recency and by concentration. A hundred complaints spread over a year is a different signal from a hundred in a week, and analytics engines treat the burst as evidence of a campaign rather than a pattern of life. Slowing down after a spike does more than any remediation form.

Worked example

Complaints attach to the number, not the campaign, so a burst of them in March still weighs on the same number in June. That persistence is why the response is to change the pattern, not to wait it out.

Complaint rate: common questions

What complaint rate is acceptable?
No provider publishes a threshold, and the honest answer is that the rate that matters is lower than most teams expect. Treat any measurable complaint volume as a signal to change the pattern.
Do complaints affect other numbers I own?
They can. Analytics providers correlate numbers back to an originator, so a complaint pattern on one number can affect how others from the same source are scored.
How do I reduce complaints?
Call people who expect it, cap repeat attempts, respect local hours, and make the caller identity clear. Complaints come from surprise and repetition far more than from the content of the call.

Sources

  1. Combating Spoofed Robocalls with Caller ID Authentication — Federal Communications CommissionThe STIR/SHAKEN framework, the attestation levels carriers sign calls with, and the mandate requiring providers to authenticate caller ID.
  2. 47 U.S.C. § 227 — Restrictions on the use of telephone equipment — Cornell Legal Information InstituteThe Telephone Consumer Protection Act itself — the consent requirements, calling-hours limits, and private right of action.
  3. ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

See complaint rate in the product

Branded caller ID puts your business name on the recipient's screen instead of a bare number. In North America it works through CNAM, the caller-name record attached to a number, combined with STIR/SHAKEN signing that lets the terminating carrier trust the call is really from you.

Explore branded caller idGet early access