Glossary
Shrinkage
Shrinkage is the share of paid time when an agent is off the line and cannot take contacts: breaks, training, meetings, sick leave, and vacation. The Erlang formula tells you how many agents you need on the line; shrinkage tells you how many people to schedule and employ to get there.
Why it mattersIgnore it, and your schedule comes up short, so the line falls behind at peak times.
Also called: Agent shrinkage, Workforce shrinkage, Staff shrinkage
Shrinkage = paid time off the line / total paid time × 100%; People to schedule = agents needed on the line / (1 − shrinkage)Time off the line covers breaks, training, meetings, sick leave, and vacation. Time on the line waiting for a call is not shrinkage: it is part of occupancy.Example
Formula and example
An agent is paid for an 8-hour shift. On average each shift loses 1 hour to breaks and lunch, 0.5 hours to training and call reviews, and 0.3 hours to meetings. Sick leave and vacation over the year add another 0.6 hours per shift. Shrinkage = (1 + 0.5 + 0.3 + 0.6) / 8 × 100% = 30%.
If the Erlang C formula says 14 agents must be on the line, the plan needs 14 / (1 − 0.3) = 20 people. A common mistake is to add 30% to 14 and get 18: then only 18 × 0.7 = 12.6 agents are on the line on average instead of 14.
Details
Planned and unplanned shrinkage
Keep them apart: planned shrinkage is managed through the schedule, unplanned is forecast from history.
Practice
Typical values and good practice
In many contact centers shrinkage is 25-35%. Plan for less, and a schedule that looks right on paper misses the service level target: there are fewer people in the shift than the line needs.
- Measure shrinkage from agent states, not by guesswork
- Put training and meetings into low-volume hours
- Expect more sick leave in flu season and more vacation in summer
- Compare actual time with the schedule to tell shrinkage apart from schedule adherence problems
In CONTACT.WORK
How it works in CONTACT.WORK
Agent states on the live dashboards show how much of each shift goes to breaks and other off-line work. You set the shrinkage percentage in the Erlang C calculator and the shift calculator: they turn agents on the line into headcount. The workforce management module accounts for breaks, training, and absences when it builds schedules.
More
Where to use it
Backlinks
Where it appears on the site 7
Calculators 2
Blog 5
- Contact center workforce management: forecast, schedule, adherence
- How many agents does your contact center need? Erlang C in plain English
- How to build a contact center from scratch
- How to reduce average handle time without sacrificing quality
- Service level 80/20: what it means and how to choose your target
Glossary