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Glossary · Call centre operations

What is Shrinkage?

Reviewed by Sujan ThapaliyaLast updated

Definition

Shrinkage is the proportion of paid agent time not available for handling contacts: breaks, training, meetings, coaching, sick leave, and holidays. Typical shrinkage runs 30–35%, and forecasts that ignore it are always short-staffed.
The three STIR/SHAKEN attestation levels, which underpin how shrinkage 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, shrinkage included.

In practice

How shrinkage actually works

Formula: shrinkage = (total scheduled hours − productive hours) ÷ total scheduled hours × 100.

It compounds with occupancy targets. Needing 10 agents on the phones at 35% shrinkage means scheduling roughly 15, not 11.

Shrinkage is also the number most often negotiated rather than measured. A contract written at 25% when the real figure is 33% does not make the team bigger; it makes every interval short by eight per cent, permanently, and the gap surfaces as missed service level that nobody can trace back to the model.

Applied after the staffing calculation, never inside it.
CategoryTypical share of paid time
Breaks and rest8–10%
Training and coaching5–8%
Meetings and admin4–6%
Holiday and sickness10–14%
Total30–35% for most voice teams

Worked example

10 agents needed on the phones ÷ (1 − 0.35) ≈ 15.4 agents to schedule.

Shrinkage: common questions

What counts as shrinkage?
Every paid hour not available for handling contacts: breaks, training, meetings, coaching, holiday, sickness and system downtime. If it is paid and not on the phone, it belongs in the number.
What is a typical shrinkage figure?
Thirty to thirty-five per cent is common for voice teams, though it varies widely by contract and season. The figure matters because staffing calculated without it is short by exactly that percentage, every day.
How does shrinkage break a staffing model?
It is applied at the end and compounds. Needing ten agents on the phone with 30% shrinkage means scheduling roughly fourteen, and a model that forgets the step produces a rota that fails every afternoon for reasons nobody can name.

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 shrinkage in the product

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