Even an excellent call center team cannot deliver consistent service when too few agents start work during the busiest interval. On the other hand, excessive staffing creates unnecessary cost and makes working time harder to use effectively. Workforce Management, or WFM, helps balance agent availability, service quality, cost and a sustainable workload for the team.
WFM is much more than creating a rota. It is a repeatable process that covers contact-volume forecasting, calculating staffing requirements, designing shifts, managing intraday deviations and learning from actual results. When implemented well, it reduces queues, overtime and last-minute schedule changes.
Why is a standard monthly schedule not enough?
Contact volume changes throughout the day, week and season. It is affected by marketing campaigns, payment dates, product launches, outages, weather, public holidays and policy changes. Two shifts with the same total number of working hours can therefore produce very different results if one fails to cover the busiest intervals.
Planning only at whole-day level hides the most important gaps. A contact center should analyse shorter intervals, typically 15, 30 or 60 minutes depending on its scale and traffic variability. This reveals when extra coverage is genuinely needed and when training, coaching or back-office work can be scheduled safely.
The four stages of Workforce Management
1. Forecast contact volume and handling time
The starting point is historical data: the number of contacts, their distribution throughout the day and average handling time. A simple average of previous weeks is not enough. Unusual events, seasonal patterns, holidays, promotions and product changes need to be identified. The forecast should also be discussed with marketing, sales, logistics and technical teams.
Forecasting should cover more than phone calls. Emails, chats, forms and messaging channels have different response requirements, but they may compete for the same employees. In an omnichannel environment, the organisation must define which channels require an immediate response and which workloads can be moved into quieter periods.
2. Calculate staffing requirements
Contact volume and average handling time describe workload, but they do not yet determine how many agents must be logged in. Phone support also depends on the target service level, acceptable waiting time and the random nature of incoming calls. Queueing models such as Erlang C are often used for these calculations and should be supported by operational experience.
Staffing should never assume that agents can remain at 100% utilisation. Without a buffer, queues grow rapidly, conversation quality falls and the team becomes overloaded. Availability, quality and cost targets should be agreed together because maximising one measure can damage the others.
3. Build the schedule
Once staffing requirements are known, they need to be converted into shifts, breaks and skill coverage. A good schedule respects employment law, contracts, employee availability, language requirements, permissions and team preferences. Having the right number of people is not enough: each interval also needs agents who can handle the required types of cases.
Flexible start times, shorter overlapping shifts, rotating duty periods and planned multitasking can help when demand varies. These arrangements still need to remain predictable for employees. Repeatedly changing schedules at short notice reduces trust and may increase turnover.
4. Manage performance in real time
Even the best forecast cannot predict every outage, absence or unexpected surge. Intraday management compares actual traffic and availability with the plan and applies proportionate corrections. Actions may include moving breaks, pausing non-urgent tasks, activating reserve coverage or changing priorities between channels.
The response should not consist of repeatedly cancelling training and breaks. If that happens regularly, the problem lies in the forecast, staffing assumptions or process design. Real-time management should correct exceptions rather than replace proper planning.
Shrinkage: the time hidden from a simple staffing plan
Shrinkage is the proportion of paid time during which an employee is not available to handle contacts. It includes breaks, training, coaching, meetings, holidays, sickness, administrative work and technical issues. Ignoring shrinkage is one of the most common reasons for understaffing.
Planned and unplanned shrinkage should be analysed separately. Planned activities can be placed outside peak periods, while unplanned shrinkage needs to be estimated from data and protected by an appropriate buffer. There is no single correct percentage for every operation. It depends on the working model, team maturity, season and type of service.
How should forecast accuracy be measured?
The forecast needs to be compared regularly with actual results. Percentage error alone can be misleading, especially during low-volume intervals, so teams should analyse both relative error and the absolute difference in contact numbers. The direction of the error also matters: systematic underforecasting creates different consequences from errors that alternate in both directions.
Accuracy should be reviewed by channel, day of the week and time interval. A monthly result may appear accurate while every marketing campaign still overloads the operation. Each significant deviation should receive a reason code so the forecasting process can learn from it.
Key WFM metrics
- forecast accuracy – how closely predicted volume and handling time match actual results,
- service level – the percentage of contacts answered within the target time,
- occupancy – the share of available time spent handling contacts and after-contact work,
- schedule adherence – how closely actual activity follows the planned schedule,
- shrinkage – the proportion of paid time unavailable for live contact handling,
- abandonment rate – the share of customers who leave the queue before being served,
- overtime and shift utilisation – the cost and stability of the staffing model.
These metrics should not be judged in isolation. Very high occupancy combined with a good service level may look efficient for a short period, but it can increase fatigue and reduce quality over time. Perfect adherence has little value when the original schedule does not match actual demand.
Schedule skills, not just headcount
In more complex operations, agents support different queues, products, languages or difficulty levels. WFM must account for skill-based routing and minimum coverage for every critical capability. Ten available agents will not solve a problem if only one can handle a technical issue or support an international customer.
A skills matrix linked to a development plan helps identify single points of dependency and plan cross-training in advance. Multiskilling improves flexibility, but frequent switching between processes can reduce productivity and quality, so it also needs to be measured.
Common staffing-planning mistakes
- forecasting only from a daily average,
- failing to include planned campaigns and business changes,
- ignoring shrinkage and absence patterns,
- treating all agents as if they had identical skills,
- constantly changing schedules at the expense of predictable working hours,
- reacting to every short-lived spike without assessing its significance,
- using adherence as a control tool rather than information about plan execution.
How can a company begin implementing WFM?
A complex platform is not required at the beginning. Start with one channel and one team, clean the historical data, choose planning intervals and define the target service level. Then prepare the first forecast, calculate staffing requirements including shrinkage, build the schedule and compare the plan with actual performance over several weeks.
Responsibility must be clear. The forecaster needs access to business information, team leaders must report events affecting availability and the operations manager should approve intraday response rules. WFM works best as a shared process rather than an isolated spreadsheet maintained by one person.
WFM in an outsourced contact center model
In outsourced contact center operations, forecasting and commercial rules should be agreed with the client. The parties need deadlines for sharing campaign information, acceptable volume deviations, scaling rules and a consistent reporting method. The operating model can then be adjusted after a pilot project and an assessment of actual statistics.
Call Center PRO has delivered customer service projects since 2008. We combine experienced agents, flexible teams, automation and AI, adapting the operating model to each client’s needs. Learn more about our inbound customer service, omnichannel support and flexible workforce solutions.
If you want to design a staffing model for a new project or improve an existing contact center, schedule a free consultation with the Call Center PRO team.