WFM Definitions

This WFM definition list guides you through the ever-changing world of workforce management, contact centers, and customer experience. It covers everything from basic abbreviations used by planners to the terminology experienced forecasters use. So the next time someone has a question about the difference between occupancy, productivity, and utilization, you are the one who can help!

We have strived to keep the WFM definitions as objective and complete as possible. However, definitions can be fluid and sometimes depend on context. If you have any questions or suggestions, please contact us, as we would be happy to discuss them with you. To reach the next-level and learn more about basic or advanced WFM, check out our (online) training and consultancy pages.

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

A

Abandoned Call

A call that the customer cancels before contact with an agent is made. Related to redial and abandonment. 

ACD

Automatic Call Distributor, a part of a PABX (Private Automatic Branch eXchange) that can distribute calls that arrive on one or more numbers to extensions that are part of one or more groups that are assigned to that number.

AE

Average Excess, alternative service level definition, defined as the average time calls wait beyond the Acceptable Waiting Time (AWT).

After Call Work

Synonym of wrap-up time, the time after the end of a call that the agent spends on the call. Consist usually of entering call-related data in a computer system.

Agent

An employee who works in a Call Center is also called a (Call Center) representative (‘rep’) or CSR (Customer Sales Representative).

AHT

Average Handling Time is the time agents spend on average on a service request, usually a call, an email, or a chat, including the wrap-up time. It is related to handling time.

Algorithm

A step-by-step method to solve a specific, often computational, problem.

Analytics

Also known as business analytics, a fact-based approach to business process and product improvement using advanced mathematics and ICT.

ANI

Automatic Number Identification is a technique used to identify customers by their telephone numbers. Used in combination with CTI (Computer-Telephony Integration) to show customer information immediately on the agent’s computer screen.

ASA

Average Speed of Answer is the average time a call waits before being connected to an agent.

AWT

Acceptable Waiting Time, the target upper bound to the waiting time, often equal to 20 seconds, is used in the Service Level (SL) definition. It is also called Time to Answer (TTA) and Service Time (ST).

B

B2B

Business-to-business, relative to commercial activities between businesses.

B2C

Business-to-consumer, relative to commercial activities between business and end-consumers.

BPO

Business Process Outsourcer is a company that offers call center services, often to multiple organizations at the same time, regularly from a cheaper off-shored location such as India or the Philippines.

C

Call Blending

A way of handling different call queues, for example, inbound and outbound calls, simultaneously by assigning them dynamically to one or multiple agent groups. Call blending is often implemented as a way of maximizing occupancy.

Call Center

A collection of resources (typically agents and ICT equipment) capable of delivering services by telephone.

Call Center Arithmetics

Basic WFM calculations based on totals and averages, without taking fluctuations and flexibility into account. Related to call center mathematics.

Call Center Mathematics

Advanced WFM calculations that go beyond call center arithmetics, taking fluctuations and flexibility into account. Related to call center arithmetics.

Channel

In the context of contact centers, a means to have contact with customers. Examples are telephony, fax, and the internet.

Contact Center

A collection of resources (typically agents and ICT equipment) capable of delivering services through multiple communication channels.

Cost Center

From Wikipedia: ”In business, a cost center is a division that adds to the cost of an organization, but only indirectly adds to its profit. Typical examples include Research and Development, Marketing, and Customer service.”

CRM

Customer Relationship Management is mainly used to denote computer systems that allow recording and retrieving interactions with the customer. CRM systems made the advent of call centers possible.

Cross-trained

Denotes an agent with more than one skill and thus can handle more than one type of call. A generalist is fully cross-trained. Also denoted as X-trained.

CTI

Computer-Telephony Integration is the process that enables the communication between and integration of telephone equipment and computer systems.

D

Data Mining

A field of science aimed at discovering relations in data. It significantly overlaps with statistics, but it is less mathematical, having origins in computer science.

Decimal Separator

The Decimal Separator is the character used to indicate where the fractional part of a number begins and where the integer part ends.

The symbol used for the decimal separator differs per country and is either a dot ‘.’ or a comma ‘,’. Because of this, the decimal separator also differs between versions of Excel.

Within CCmath, we use the English version of Excel. Therefore we use the dot as the decimal separator.

DNIS

Dialed Number Identification Service, a part of the ACD (Automatic Call Distributor) that recognizes the calling number.

E

Erlang

Danish mathematician who created the safety staffing models as well as the dimensionless unit of load.

Erlang C

A safety staffing model that considers fluctuations in the number of arrivals and handling times.

Erlang X

A safety staffing model that, in addition to the Erlang C model, takes abandonments and retrials into account.

F

FCFS

First Come First Served refers to the orders in which queued calls are served: in the order of arrival.

FCR

First Call Resolution applies when a call is handled right the first time, not necessitating a second call. The FCR rate is the fraction of the first calls for which this is the case. Related to reconnect.

Forecasting

The prediction of (exogenous) variables such as call volume, AHT (Average Handling Time), and patience.

G

Generalist

An agent with all skills and/or can handle all types of calls.

Gross Workforce

Measure of the workforce that is equal to the net workforce plus shrinkage.

Gross Workload

Measure of the workload, which is equal to the net workload plus safety staffing. Equal to the net workforce.

H

Handling Time

The time spent to handle a service request that can be calculated over the following PABX (Private Automatic Branch eXchange) metrics: Handling time = Ring time + Talk time + Hold time + Transfer time + Wrap-up time. Related to AHT (Average Handling Time).

I

ICT

Information and Communication Technology, technology relative to computers and technology-assisted communication.

Intra-Day Management

Synonym of Real-Time Performance Management, the activity has as the goal on the day of execution to take actions to obtain the required service level as well as possible.

L

LIA

Longest idle agent, an agent selection rule used in an ACD (Automatic Call Distributor) mechanism. The agent with the longest idle time since their last phone activity (after call work) will be offered the next call.

Load

Amount of work offered to the system, defined by the product of the forecast and the AHT (Average Handling Time), measured in Erlang. For example: if the forecast of the arrival rate is 4/min and the AHT is 3 minutes, then the load is 4 * 3 = 12 Erlang.

LWC

Longest Waiting Call, a call selection rule used in multi-skill call centers.

M

Mean

The mean (or average) of a series of numbers of length n is defined as the sum of the numbers in the series divided by n. In formula form, this is shown as follows:

𝐴𝑉=1𝑛∑𝑛𝑖=1𝑎𝑖=1𝑛(𝑎1+𝑎2+𝑎3+⋯+𝑎𝑛)

For example: if our series of numbers is 1 2 3 4 5, then the mean is equal to 15×(1+2+3+4+5)=15×15=3.

The Excel function for the mean is AVERAGE()

Metrics

Quantitative measures that are commonly used for assessing, comparing, and tracking the performance of a system. In a contact center, a group of metrics is often displayed in a dashboard for analysis and decision support. For example, Handling time, Occupancy, Shrinkage, Longest Idle Agent, etc.

Model

A description in mathematics terms of part of a system that allows an analysis of certain aspects of that system. For example, a simulation model.

N

Net Workforce

Equal to gross workload.

Net Workload

The amount of agent time needed to handle a certain amount of work without accounting for safety staffing. For example, if there are 1000 calls with an AHT of 4 minutes during the day, then the net workload is 4000 minutes.

Noise

Informal statistical term meaning unexplained variability (as in Poisson noise).

O

Occupancy

The time that an agent handles calls (talk time plus wrap-up) is divided by the total time that the agent is available for handling calls. It can be calculated by; net workload / gross workload or net workload/net workforce. Not to be confused with utilization or productivity.

Offered load

Amount of work offered to the system, defined by the product of the forecast and the AHT (Average Handling Time), measured in Erlang. For example: if the forecast of the arrival rate is 4/min and the AHT is 3 minutes, then the load is 4 * 3 = 12 Erlang.

OR

Operations Research is the science that uses mathematical models to improve business operations. Also known as Management Science, therefore sometimes called OR/MS. See also Informs.org.

Order of Operations

When we speak about operations mathematically, it means adding, subtracting, multiplying, dividing, squaring, etc. Remember: If it is not a number, it is probably an operation.

When you see something like …

7 + (6 × 52 + 3)

… what part should you calculate first? 

Start at the left and go to the right. 

Or go from right to left?

Warning: Calculate them in the wrong order, and you will get the wrong answer!

So long ago, people agreed to follow rules when doing calculations, and they are:
Do things in Parentheses First. Example:

yes 6 × (5 + 3)=6 × 8=
48
 
no 6 × (5 + 3)=30 + 3=
33
(wrong)

Exponents (Powers, Roots) before Multiply, Divide, Add or Subtract. Example:

yes 5 × 22=5 × 4=
20
 
no 5 × 22=102=
100
(wrong)

Multiply or Divide before you Add or Subtract. Example:

yes 2 + 5 × 3=2 + 15=
17
 
no 2 + 5 × 3=7 × 3=
21
(wrong)

Otherwise, go left to right. Example:

yes 30 ÷ 5 × 3=6 × 3=
18
 
no 30 ÷ 5 × 3=30 ÷ 15=
2
(wrong)

How Do I Remember It All … ? PEMDAS!

P
Parentheses first
E
Exponents (i.e., Powers and Square Roots, etc.)
MD
Multiplication and Division (left-to-right)
AS
Addition and Subtraction (left-to-right)

source: mathisfun.com

P

PABX

Private Automatic Branch eXchange (PABX or PBX) is a telephone exchange used privately by a company.

Patience

The amount of time a customer is willing to wait before abandoning the queue.

Planning

The organizational process of creating and maintaining a plan.

Poisson

French mathematician (1781-1840) discovered the Poisson distribution, which mathematically describes arrivals to a call center. Also used as the Poisson process, focusing on the times of arrivals, and Poisson noise, focusing on the error with respect to the forecast.

Predictive Dialer

The functionality of an ACD (Automatic Call Distributor) that allows outbound calls to be automatically initiated, anticipating the future availability of agents.

Productivity

The time an agent is available to handle calls is divided by the total time the agent is paid. It can be calculated by; gross workload / gross workforce or net workforce / gross workforce. Not to be confused with Utilization or Occupancy.

Q

Quality of Service

A synonym of Service Level, is a somewhat ambiguous term that, in the broad sense, can refer to all aspects of service (waiting time, abandonments, and so forth). In the narrow sense, it is defined as the percentage of calls answered within the AWT (Acceptable Waiting Time). The industry standard is 80/20: 80% of calls must be answered within 20 seconds. Quality of Service is a synonym of the former broader meaning.

R

Reconnect

The fact that a caller, after having been served, calls back after some time for the same service. Related to FCR (First Call Resolution).

Redial

After being abandoned or blocked, a caller calls back after some time for the same service. Related to abandonment and abandoned call.

Retrial

A caller, after being served or not, calls back for the same service. Comprises of redials and reconnects.

RTPM

Real-Time Performance Management, the activity has as the goal on the day of execution to take actions to obtain the required service level as well as possible.

S

Safety Staffing

The additional number of agents needed to reach a certain service level. The safety staffing level is often calculated utilizing the Erlang C or Erlang X formulas.

SBR

Skill(s)-Based Routing, different types of calls are routed to different agent groups based on the type of the call and the agents’ skills.

Scheduling

The process of deciding how to commit resources between various possible tasks.

Seasonality

A forecasting term that means a pattern repeats itself in call centers typically at intra-day, intra-week, and intra-year levels.

Short Abandon

A call that was abandoned very quickly made it unlikely that the caller was already tired of waiting.

Shrinkage

The fraction of paid time that an agent is not available to take calls because of holidays, training, paid breaks, etc.

Below you can see an example of a shrinkage table. It is important to note that this is merely an example of how shrinkage is calculated. Many more activities can be added, and not all activities are relevant for all companies.

Workforce management hours

Simulation

The activity of mimicking a real-world system over time is usually performed with a computer to evaluate the performance of such a system.

Skill Group

A group of agents all having the same skill set.

Skill Set

The set of skills that an agent or group of agents have.

SL

Service Level is a somewhat ambiguous term that, in the broad sense, can refer to all aspects of service (waiting time, abandonments, and so forth). In the narrow sense, it is defined as the percentage of calls answered within the AWT (Acceptable Waiting Time). The industry standard is 80/20: 80% of calls must be answered within 20 seconds. Quality of Service is a synonym of the former broader meaning.

SLA

Service Level Agreement, is the contract between a business unit and higher management or an outsourcer with its client company concerning the required service levels.

Specialist

An agent who can only handle one type of call. It can also mean an agent who can do even the most difficult calls, contrasting with a generalist. To avoid ambiguity, it is better to use the term single-skilled agent.

SSF

Single Skill First, an agent selection rule is used in multi-skill call centers that assigns calls to agents with the least number of skills.

ST

Service Time, the target upper bound to the waiting time, often equal to 20 seconds, is used in the service level definition. It is also called Time to Answer (TTA) and Service Time (ST).

T

Traffic Management

Synonym of Real-Time Performance Management, the activity has as the goal on the day of execution to take actions to obtain the required service level as well as possible.

TSL

Telephone Service Factor, related to Service level (SL).

TTA

Time To Answer, related to Acceptable Waiting Time (AWT).

U

Utilization

The time that an agent handles calls (talk time plus wrap-up time) is divided by the total time the agent is paid. It can be calculated by: net workload / gross workforce. Utilization = occupancy * productivity. Not to be confused with productivity or occupancy.

V

VRU

Voice Response Unit is part of an ACD (Automatic Call Distributor) that allows customers to enter information by responding to instructions through the telephone’s keypad or the VRU (Voice Response Unit).

W

Waiting Time

The time a call spends between entering the queue (often after a recorded message or after having been chosen by a Voice Response Unit) and an agent is connected to the call.

Weighted Mean***

The weighted mean is similar to the general mean, except that some points contribute more to the mean than others. Mathematically if we have a set of points 𝑎𝑛 and a set of weights 𝑤𝑛 that belong to the points, then the weighted average is equal to

𝑊𝐴𝑉=𝑛𝑖=1𝑎𝑖𝑤𝑖𝑤𝑖=𝑎1𝑤1+𝑎2𝑤2++𝑎𝑛𝑤𝑛𝑤1+𝑤2++𝑤𝑛WAV=∑i=1naiwiwi=a1w1+a2w2+⋯+anwnw1+w2+⋯+wn

for example, if we have two sets of points, 1 2 with weight 1 and 3 4 5 with weight 2, then the weighted average of all points is equal to

1×1+2×1+3×2+4×2+5×21+1+2+2+2=1+2+6+8+101+1+2+2+2=278=3.3751×1+2×1+3×2+4×2+5×21+1+2+2+2=1+2+6+8+101+1+2+2+2=278=3.375

In Excel, there are two ways to calculate the weighted average. Say we have the values in column A and the weights in column B.

In the first method, we set the product of A and B in column C. Then, the weighted average is given by WAV = SUM(C:C)/SUM(B:B)

The second method uses the sumproduct function. This method doesn’t require an additional column to be used. WAV = SUMPRODUCT(A:A,B:B)/SUM(B:B)

WFM

Workforce Management consists of all activities from forecasting and planning to online control, thus everything that has to do with the employment of agents in a contact center.

WFM Tool

A computer tool that assists planners with their WFM tasks. It minimally consists of forecasting, Erlang C, and agent scheduling modules.

WFO

Workforce Optimization includes WFM, call monitoring, and agent performance management.

Workforce

The amount of available or required agent time when used in capacity calculations. It can be the net or gross workforce and should match the workload.

Workload

The amount of work on incoming call volume during a certain amount of time is usually measured in minutes. It can be measured without safety staffing (net workload) or with safety staffing (gross workload). Not to be confused with the offered load.

Wrap-up Time

Time after the end of a call that the agent spends on the call. Consist usually of entering call-related data in a computer system.

X

X-trained

Abriavation of Cross-trained. Denotes an agent with more than one skill and can thus handle more than one type of call. A generalist is fully cross-trained. 

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