Free tools · Glossary
The language of workforce management.
Plain definitions of the terms planners use every day — with the formula where there is one, the calculator that works it out, and where WFMPro handles it.
All free toolsGlossary
The basics
The discipline, and the units everything else is built from.
- Workforce management (WFM)
The discipline of having the right number of people, with the right skills, available at the right times — at a cost the operation can sustain. In practice it covers forecasting, capacity planning, scheduling and managing the working day.
See also Forecast, Capacity planning, Schedule, Intraday management
- Queue
Where contacts wait for an agent. Most operations run several, split by contact type, language or customer, each with its own forecast and its own service level.
See also Planning group, Skill-based routing
- Planning group
Queues and agents grouped so they are forecast and scheduled together, usually because the same people serve them. Drawing the groups wrongly undermines the maths inside them, however good it is.
- Interval
The time slice a plan is built in, usually 15 or 30 minutes. Demand, staffing and service level are worked out per interval because a daily total hides the peaks that decide whether customers wait.
See also Intraday pattern, Coverage
Glossary
Demand and forecasting
How much work is coming, and how well the last forecast predicted it.
- Contact volume
The number of contacts — calls, chats, emails, cases — arriving in a period. The raw input to every forecast and every staffing calculation.
- Average handle time (AHT)Also called handle time
The average time a contact takes from start to finish: talking or chatting, hold, and the wrap-up work after the customer has gone. With volume, it sets the workload.
See also After-contact work (ACW), Workload
- After-contact work (ACW)Also called wrap-up or after-call work
The work an agent does once the customer has gone — notes, dispositions, follow-up. It belongs in handle time; leaving it out understates the staff a queue needs.
See also Average handle time (AHT)
- Workload
Volume multiplied by handle time: the hours of work that demand actually creates. It is what the staffing maths turns into people.
Workload = contacts × average handle time
See also Contact volume, Average handle time (AHT), Erlang
- Forecast
An estimate of future volume and handle time, interval by interval. Headcount plans, schedules and the intraday plan all inherit its errors, which is why accuracy is measured rather than assumed.
In WFMPro: Forecasting & demand
See also Forecast accuracy, Seasonality, Reforecast
- Seasonality
Patterns in demand that repeat — by time of day, day of week and time of year. Most of a forecast's shape comes from seasonality; the rest from trend and from known events such as a campaign or a billing run.
See also Forecast, Intraday pattern
- Intraday patternAlso called intraday curve or distribution
How a day's volume is spread across its intervals. Two days with the same total can need very different staffing if one of them peaks sharply mid-morning.
See also Interval, Seasonality
- Forecast accuracy
How close a forecast came to what actually happened, measured after the fact. MAPE, WAPE and bias each answer a different question, so a single accuracy percentage can hide the problem that matters.
Forecast accuracy calculatorIn WFMPro: Forecasting & demand
See also MAPE, WAPE, Forecast bias
- MAPEAlso called mean absolute percentage error
The average of each interval's error as a share of that interval's actual volume. Every interval counts equally, so quiet intervals with small actuals can dominate it. Intervals with no actual volume can't be divided by and are left out.
MAPE = average of |forecast − actual| ÷ actual
See also WAPE, Forecast accuracy
- WAPEAlso called weighted absolute percentage error
Total absolute error divided by total actual volume. Busy intervals carry more weight, which usually matches where forecast errors cost money.
WAPE = Σ |forecast − actual| ÷ Σ actual
See also MAPE, Forecast accuracy
- Forecast bias
Whether a forecast runs consistently high or low. Positive bias means over-forecasting, which pays for idle time; negative bias means under-forecasting, which makes customers wait. A forecast can have small errors and still be biased.
Bias = (Σ forecast − Σ actual) ÷ Σ actual
See also Forecast accuracy, WAPE
- Reforecast
Updating a forecast part-way through a day or week once actuals start arriving, so the rest of the plan reflects what is actually happening.
In WFMPro: Real-time & agentic operations
See also Forecast, Intraday management
Glossary
Staffing and capacity
Turning workload into the number of people a period needs.
- ErlangAlso called traffic intensity
The unit of workload in queueing maths: one Erlang is one hour of work arriving per hour. A hundred three-minute contacts in a 30-minute interval is 10 Erlangs.
Erlangs = contacts × AHT ÷ interval length (in the same units)
- Erlang C
The queueing formula widely used to turn workload into the number of agents needed for a service-level target. It assumes every contact waits until answered, so on queues where many people hang up it can overstate the staff required.
Erlang C staffing calculatorIn WFMPro: Forecasting & demand
See also Erlang, Service level, Erlang B, Simulation staffing
- Erlang B
The formula for systems where a contact that can't be served straight away is lost rather than queued — first used to size telephone trunk lines. Erlang C is calculated from it.
See also Erlang C
- Service level
The share of contacts answered within a target time, written as a pair: 80/20 means 80% answered within 20 seconds. A widely used staffing target, and the one the Erlang C calculator plans to.
See also Average speed of answer (ASA), Erlang C, Abandonment rate
- Average speed of answer (ASA)
The average time contacts wait before an agent answers, including those answered at once. Two queues with the same ASA can feel very different — everyone waiting a little, or a few people waiting a long time.
See also Service level, Abandonment rate
- Abandonment rate
The share of contacts that hang up or leave before an agent answers. It climbs as waits lengthen, and it is the main thing Erlang C leaves out.
See also Service level, Erlang C, Simulation staffing
- Occupancy
The share of available time agents spend handling contacts rather than waiting for the next one. Very high occupancy looks efficient but leaves no slack — the usual reason a plan that meets its service level still wears people out.
Occupancy = handling time ÷ available time
Occupancy and utilisation calculator
See also Utilisation, Service level
- Utilisation
The share of paid time agents are available to work. Occupancy measures how busy that available time is; utilisation measures how much paid time becomes available time in the first place.
Utilisation = available time ÷ paid time
- Shrinkage
Paid time when agents aren't available to handle contacts — breaks, training, meetings, coaching, sickness, holiday. A plan without it under-staffs every interval by exactly the share that is lost.
Shrinkage = unavailable paid hours ÷ paid hours
Shrinkage calculatorIn WFMPro: Forecasting & demand
See also Required and rostered staff, Absenteeism, Utilisation
- Full-time equivalent (FTE)
A unit of staffing, not a person: one FTE is one full-time contract's worth of hours. Two half-time agents make one FTE. Plans are built in FTE and turned into people at the end.
Capacity and FTE calculatorIn WFMPro: Workforce planning & headcount
See also Capacity planning, Required and rostered staff
- Required and rostered staffAlso called net and gross staffing
Required staff is how many agents an interval needs handling contacts. Rostered staff is how many to schedule once shrinkage has taken its share.
Rostered = required ÷ (1 − shrinkage)
See also Shrinkage, Full-time equivalent (FTE)
- Capacity planning
Turning a forecast into the headcount needed weeks or months ahead, and deciding how to close the gap with the people you have — hiring, training, overtime.
Capacity and FTE calculatorIn WFMPro: Workforce planning & headcount
See also Staffing gap, Full-time equivalent (FTE), Forecast
- Staffing gap
The difference between the people a plan needs and the people available. A gap that recurs every week is structural, and the question becomes whether overtime or hiring closes it more cheaply.
Overtime vs. hire calculatorIn WFMPro: Workforce planning & headcount
See also Capacity planning, Overtime
- Simulation staffing
Working out staffing by simulating contacts arriving and being handled, instead of using a formula. Slower than Erlang C, but it can model what the formula leaves out, such as abandonment and contacts waiting for a particular skill.
In WFMPro: Scheduling & optimization
See also Erlang C, Abandonment rate, Skill-based routing
Glossary
Scheduling
Putting those people in the right intervals, within the rules they work under.
- ScheduleAlso called roster or rota
Who works when, and what they do in each interval — handling contacts, on a break, in training. A good schedule puts people where the forecast says they are needed, within the rules they are employed under.
In WFMPro: Scheduling & optimization
See also Shift, Coverage, Schedule efficiency
- Shift
One working period for one agent: a start, an end, and the breaks and activities between them.
See also Schedule, Break placement
- Coverage
The staff a schedule provides in each interval, compared with the staff required. Too little and customers wait; too much and the operation pays for idle time.
In WFMPro: Scheduling & optimization
See also Schedule, Interval, Schedule efficiency
- Schedule efficiency
How closely a schedule's coverage follows requirement across the day. A schedule can supply the right total hours and still be inefficient if the hours fall in the wrong intervals.
In WFMPro: Scheduling & optimization
See also Coverage, Break placement
- Skill-based routing
Sending each contact to an agent with the skill it needs — a language, a product, a level of authority. It makes scheduling harder, because coverage has to be right for each skill as well as overall.
In WFMPro: Scheduling & optimization
See also Multi-skilling, Queue, Simulation staffing
- Multi-skilling
Training agents to handle more than one type of contact. It gives a schedule more room to cover peaks, at the cost of training time and a longer time to proficiency.
See also Skill-based routing
- Break placement
Positioning breaks and lunches within shifts so they fall in quieter intervals. Small moves can recover coverage at the peak without adding a single paid hour.
- Schedule fairness
Spreading unpopular hours — nights, weekends, holidays — evenly across a team over time, rather than letting them fall on the same people week after week.
- Shift swap
Two agents exchanging shifts. It works when the swap is checked against the same rules as the original schedule, so it can't quietly open a gap or break a working-time rule.
In WFMPro: Agent experience & engagement
See also Shift marketplace, Schedule
- Shift marketplaceAlso called open shifts
A place where extra or released shifts are posted for eligible agents to claim, rather than being allocated by a manager.
In WFMPro: Scheduling & optimization
See also Shift swap, Voluntary time off (VTO), Overtime
- Shift bidding
Agents ranking the shift patterns they want, with patterns then awarded by an agreed rule such as seniority or performance.
See also Schedule fairness, Shift
Glossary
Running the day
Comparing the day as it happens with the plan, and acting on the difference.
- Intraday management
Running the day as it happens: comparing actual volume and staffing with the plan interval by interval, and acting when the two drift apart.
In WFMPro: Real-time & agentic operations
See also Real-time adherence (RTA), Reforecast, Voluntary time off (VTO)
- Schedule adherence
How closely agents follow their schedules in time — handling contacts when scheduled to, on break when scheduled to.
Adherence = minutes in adherence ÷ scheduled minutes
Schedule adherence calculatorIn WFMPro: Real-time & agentic operations
See also Conformance, Real-time adherence (RTA)
- Conformance
Whether agents worked the total time they were scheduled for, regardless of when. Perfect conformance with poor adherence means the right hours at the wrong times.
Conformance = minutes worked ÷ scheduled minutes
See also Schedule adherence
- Real-time adherence (RTA)
Checking adherence continuously through the day, so a supervisor sees someone out of adherence while it can still be put right — not in tomorrow's report.
In WFMPro: Real-time & agentic operations
See also Schedule adherence, Intraday management
- Voluntary time off (VTO)
Offering agents unpaid time off when the day turns out overstaffed. Cheaper than paying for idle time, and often welcome.
In WFMPro: Agent experience & engagement
See also Intraday management, Overtime, Shift marketplace
- Overtime
Paying for extra hours, usually at a premium, to cover a shortfall. Sensible for a short-term gap; expensive as a permanent fix.
Overtime vs. hire calculatorIn WFMPro: Agent experience & engagement
See also Staffing gap, Voluntary time off (VTO)
Glossary
People and cost
What the operation spends, and what it loses when people leave.
- AttritionAlso called staff turnover
The rate at which people leave, as a share of average headcount. Each leaver costs recruitment and training, and the weeks before a replacement is fully productive.
Attrition = leavers ÷ average headcount
Attrition rate and cost calculatorIn WFMPro: Agent experience & engagement
See also Absenteeism, Schedule fairness
- Absenteeism
Unplanned absence — sickness and no-shows. Part of shrinkage, and the hardest part to plan for, because it doesn't arrive on a schedule.
- Cost per contact
Total operating cost divided by the contacts handled. Labour is usually the largest part of it, so staffing accuracy moves this number directly.
Cost per contact = total cost ÷ contacts handled
- Gross pay preparation
Working out each person's hours and pay elements from what they actually worked, ready to hand to a payroll provider. It is not payroll itself — tax, deductions and filing happen afterwards, elsewhere.
In WFMPro: Payroll preparation
See also Schedule adherence, Overtime
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