Call & Contact Center Glossary

A comprehensive glossary of essential call center definitions and terms in the areas of quality assurance, agent training, and customer experience.

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Attrition rate

Attrition refers to the rate of employees that leave your call center (either voluntarily or involuntarily). While attrition rate is often used interchangeably with turnover rate, there is a key difference. If you aim to fill the leaving employee’s position, you’re dealing with turnover. And if you choose not to look for a replacement (for example, if they retired or you removed the position altogether), you’re looking at attrition. Where the former is most likely a reason for concern, the latter can be an effective cost-saving tactic.

To calculate the attrition rate, divide the number of employees who left your call center during a certain period by the average number of employees for that same period and then multiply it by 100.


Automatic Call Distribution (ACD) 

Automatic Call Distribution (ACD) is a technology that routes incoming calls to the most appropriate agents based on their skills, availability, or the caller’s specific needs. If used effectively, ACD can help reduce wait times, improve First Call Resolution (FCR), and improve the overall customer experience.


Average Handle Time (AHT) 

Average Handling Time (AHT) calculates the average amount of time your agents spend on resolving customer service calls. Aside from the actual interaction, AHT includes hold times, delays, transfers, and follow-up tasks. Once you’ve added all of these together, divide the total by the number of calls.

Learn more about Average Handling Time




Business Process Outsourcing (BPO)

BPO refers to the practice of hiring a third-party service provider to handle certain business operations. In the context of a call center, BPO means outsourcing customer service and support tasks to an external vendor.




Call script

A call script is a document that contains clear instructions on the best ways for agents to handle customer interactions. It provides them with guidance and precise wording they can use in response to a specific customer question or issue.

Learn more about call center call script


Contact Center as a Service (CCaaS)  

Contact Center as a Service (CCaaS) is a cloud-based solution that provides companies with the tools and technology needed to effectively manage their customer experience. CCaaS platforms often include features like IVR, call recording, omnichannel support, and more, and help companies reduce costs and scale their operations.


Customer Satisfaction (CSAT) 

Customer Satisfaction (CSAT) is an essential metric used to assess how satisfied a customer is with a product or the overall experience. In a call center environment, CSAT would determine how happy a customer is with the provided service. The most common way to determine the level of customer satisfaction is by running a feedback survey.




Dead air

In a call center, dead air refers to a period of silence during an interaction where the customer is left waiting while the agent is looking up information, checking with other team members, dealing with a slow system, or figuring out the best next steps. Some of the reasons for dead air include lack of knowledge, insufficient training, outdated or faulty technology, and inefficient processes.

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Dialed Number Identification Service (DNIS) 

Dialed Number Identification Service (DNIS) is a telecommunication technology that helps identify and route calls based on the dialed phone number. Call centers can use DNIS to better direct the calls to relevant agents through Automatic Call Distribution (ACD).


DSAT Score 

The opposite of CSAT, DSAT stands for customer dissatisfaction and refers to the percentage of customers that are unhappy with their experience. The easiest way to calculate it is by subtracting the CSAT score from 100 (your ultimate satisfaction score).

Learn more about DSAT score




Empathy statements 

Empathy statements are phrases used by contact center agents to demonstrate the ability to listen, relate, and sympathize with a customer. Genuine empathy is an essential quality of a good call center agent as it allows them to better understand customers and their needs.

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A call escalation is a process where the call is transferred to a supervisor or a different agent, as the original agent is unable to resolve the customer’s issue or complaint.

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First call resolution

First call resolution (FCR) is a metric that estimates the agent’s ability to handle and resolve a customer’s issue during the first call without the need for further follow-up.

To calculate the first call resolution, divide the number of support issues resolved during the initial call by the total number of FCR-eligible support issues.

Learn more about First Call Resolution (FCR)




Grade of Service

Grade of Service (GOS) is a percentage of inbound calls answered within a certain time frame.




Hold time 

Hold time (or Holding time) is the amount of time a caller spends ‘on hold’ and waiting for an agent’s response during a customer call.




Inbound calls  

Inbound calls refer to incoming calls from customers requiring support or assistance from call center agents.


IVR call center

Interactive Voice Response (IVR) is an automated phone technology that uses pre-recorded responses and allows incoming callers to access information without needing to speak to an agent. IVR call centers use this technology to streamline their operations and reduce waiting times.




Jitter buffer 

Jitter buffer is a tool for managing voice packets on VoIP calls to improve voice call quality and ensure seamless communication with a customer.




Key Performance Indicator (KPI) 

Also known as Key Performance Indicators, KPIs are the most critical metrics that reflect how well a call center performs against its key objectives. Most often, call center KPIs are built around customer experience, productivity, agent performance, and generated revenue or accumulated costs.

Learn more about call center KPIs


Knowledge Process Outsourcing (KPO) 

Knowledge Process Outsourcing (KPO) refers to outsourcing knowledge-based services that require a high level of specialized expertise. KPO can be considered an extension of BPO (Business Process Outsourcing).




Learning Management System (LMS)  

LMS is a centralized software solution that automates the training process and learning activities within an organization. In call centers, Learning Management Systems can be used to provide automated training on compliance, customer engagement, soft agent skills, and more.

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Call center logs are the records of customer calls that usually contain data such as the call time stamp, origin and duration, caller’s number, and other details. Call logs can be essential for call center compliance and quality assurance purposes.




Mean Opinion Score (MOS)

MOS, also known as Mean Opinion Score, refers to a scoring system used to assess the quality of voice communication during calls. Customers are typically asked to rate the quality of the call on a scale of 1 to 5. A higher MOS indicates better call quality, which contributes to overall customer satisfaction.




No call, no show (NCNS)

No call, no show refers to a scenario where an employee doesn’t show up for work without informing their employer. In a call center, this most commonly involves an agent failing to communicate their absence to a supervisor. Unlike pre-approved days off, NCNS can cause significant disruption of the call center processes and add extra strain on the rest of the team.

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Net Promoter Score (NPS)

Net Promoter Score, commonly known as NPS, is a standard metric used to assess customer experience and loyalty. It is based on the customers’ answers to a single post-interaction question: “On a scale of 0 to 10, how likely are you to recommend our company/product/service to a friend or colleague?”

Based on their answers, responders are grouped into: Promoters (score 9-10) - highly satisfied and loyal customers likely to recommend your brand; Passives (score 7-8) - customers who are less enthusiastic and are unlikely to have an impact on your company; and Detractors – dissatisfied customers who can potentially harm your brand’s reputation and hinder growth. To calculate NPS, you need to subtract the percentage of Detractors from the percentage of Promoters.

Learn more about call center NPS




Outgoing call  

In a call center, an outgoing call refers to proactive communication initiated by an agent. Unlike an incoming or an inbound call, where a customer contacts the center to resolve their query, an outgoing call usually involves agents reaching out to customers to generate leads, gather feedback, or provide important updates.


Omnichannel contact center

An omnichannel or multichannel contact center provides customers with a seamless experience across various communication channels, offering them the flexibility to interact with the company in the way that suits them. Unlike traditional call centers that mainly rely on phone calls, omnichannel centers also offer centralized support via email, live chat, social media, and SMS.

Learn more about omnichannel contact center




Probing questions  

In a call center environment, probing questions refer to specific questions agents use during an interaction to get a deeper understanding of a customer’s needs, issues, or concerns.

Probing questions are typically open-ended and encourage customers to elaborate on or clarify their inquiries so that agents can identify the root cause of the problem, offer an appropriate and personalized solution, and enhance customer satisfaction.

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Quality Assurance (QA)

Quality Assurance (or QA) is a systematic approach that ensures that a company maintains a certain performance level and meets established customer standards. QA programs focus on monitoring and evaluating interactions between agents and customers to ensure that the former deliver excellent customer experience, remain compliant and efficient, and achieve the set KPIs.



A call center queue forms when a customer is put on hold while waiting for an agent’s response. Typically, contact centers use the automatic call distributor (ACD) to direct incoming calls to the most suitable agents. Most modern call centers use virtual queuing, where a caller remains on a virtual “waiting list,” without having to physically stay on the phone. Once an agent becomes available, they can call the customer back, minimizing the waiting times.

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Repeat calls

Repeat calls refer to the instances where a customer reaches out to the call center for the same or related issue shortly after their initial inquiry. Repeat calls severely impact customer satisfaction and can indicate existing product/service problems, an agent’s lack of skill or appropriate training, operational inefficiencies, and more.

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Retention rate

Retention rate refers to the percentage of customers who continue doing business with the company (buying its products or using services) after their initial interaction. This call center KPI is essential for measuring customer loyalty and satisfaction.

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Speech analytics

Call center speech analytics refers to an advanced technology that analyzes the recorded contact center calls to determine patterns and gain insights into customer behavior and agent performance.

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Skill based routing

In a call center, skill-based routing refers to a method used to direct incoming calls to the most suitable agent based on their specific skills, knowledge, and expertise. Assigning a customer query to a relevant agent helps improve metrics like first call resolution (FCR) and average handling time (AHT), as well as enhance customer satisfaction.




Trouble ticket

A trouble ticket, also known as a support or service ticket, is a record linked to a customer request or query and describing the issue, customer details, and other relevant information. In a call center, the ticket can be assigned to an agent who can address the query or, if needed, forward it to a relevant technician.


Turnover rate

The turnover rate refers to the percentage of employees who leave an organization or are replaced during a specific time period. Call centers are notorious for having a high turnover rate of 30% to 45% on average, which leads to increased hiring and training costs, reduced productivity, and potentially decreased customer satisfaction.





Upselling is a sales technique where an agent attempts to persuade a customer to purchase a premium and more expensive version of the product or service they currently use or intend to buy. Unlike cross-selling, where a customer is encouraged to buy complimenting products, upselling specifically targets upgrades, enhancements, and higher-tier offerings.




Voice of the customer (VOC)

Voice of the customer (also known as VOC) refers to the process of capturing and analyzing customer feedback to assess customer expectations, needs, and preferences, as well as their customer experiences, attitude towards the company, and the overall satisfaction. Collecting VOC information is essential for streamlining call center operations, improving agent performance, and enabling informed business decisions.


VoIP caller

VoIP caller refers to a person who is using the Voice over Internet Protocol (VoIP) technology to make a phone call. Instead of the typical cell towers, wires or fiber optic cables, VoIP calls are routed using internet connection, which means that VoIP callers can make calls directly from their computers, smartphones or other data-powered devices.




Workforce engagement management (WEM)

Workforce engagement management (WEM) refers to a comprehensive, employee-focused approach to creating a working environment that helps enhance agent performance, engagement, and productivity. WEM uses various strategies, including workforce scheduling, performance management, quality monitoring, quality assurance, and more. Engaged agents are much more likely to be more productive, committed and satisfied, and WEM directly contributes to decreasing turnover rates and improving customer satisfaction.


Workforce management (WFM)

Call center workforce management is a strategic approach to ensuring that agents are in the right place at the right time, delivering optimal performance and meeting customer expectations. WFM goes beyond scheduling shifts and assigning tasks, and also involves components such as forecasting, skill based routing, determining optimal workload, performance management, and more.

Learn more about call center workforce management