WFM Metrics & Terminology
A comprehensive reference guide to all key Workforce Management metrics with definitions, examples, and formulas.
Service Level
Definition: The percentage of customer calls answered within a predefined time threshold, commonly expressed as X% of calls answered within Y seconds.
Example: If 1,000 calls are offered and 850 are answered within 20 seconds, the service level is 85%.
Formula
(Calls Answered within Threshold Time) ÷ (Calls Offered − Abandoned Calls within Threshold Time)
Occupancy
Definition: The proportion of an agent's logged-in time spent actively handling customer interactions including talk time, hold time, and after-call work.
Example: An agent logged in for 8 hours and spent 6 hours handling calls has an occupancy of 75%.
Formula
(Talk time + Hold time + ACW) / (Talk time + Hold time + ACW + Idle time) × 100
Utilization
Definition: Measures how effectively paid agent time is used, including both productive and available time.
Example: If an agent is paid for 9 hours and spends 7.5 hours working or available, utilization is 83%.
Formula
(Total Handled Time + Available Time) / (Total Handled Time + Available Time + Auxiliary Time (Paid))
Shrinkage
Definition: The percentage of scheduled agent time that is not available for handling customer contacts due to breaks, training, meetings, leaves, or system issues.
Example: If agents are scheduled for 100 hours but only 75 hours are available, shrinkage is 25%.
Formula
(In-Office Shrinkage + Out-of-Office Shrinkage) ÷ Total Scheduled Hours
Attrition Percentage
Definition: The percentage of employees who leave the organization or transfer internally during a given period.
Example: If 10 agents leave during a month and the average headcount is 200, attrition is 5%.
Formula
Attrition Headcount / ((Opening Headcount + Closing Headcount) / 2)
ASA (Average Speed of Answer)
Definition: The average time customers wait in queue before their call is answered by an agent.
Example: If customers wait a total of 5,000 seconds for 250 answered calls, ASA is 20 seconds.
Formula
Total Calls Wait Time / Calls Answered
Total Wait Time
Definition: The cumulative time spent by all callers waiting in the queue before their calls are answered.
Example: If 100 callers wait an average of 30 seconds, total wait time is 3,000 seconds.
Formula
Sum of individual caller wait times
Abandon Rate
Definition: The percentage of callers who disconnect before their call is answered.
Example: If 80 out of 1,000 callers hang up before answer, abandon rate is 8%.
Formula
Calls Abandoned / Calls Offered
Offered to Handled %
Definition: The percentage of offered calls that are successfully handled by agents.
Example: If 900 out of 1,000 calls are handled, offered-to-handled is 90%.
Formula
Calls Handled / Calls Offered
Volume % / OTF %
Definition: The ratio of actual call volume to forecasted call volume (Offered to Forecast).
Example: If forecasted calls were 10,000 but actual calls were 11,000, OTF is 110%.
Formula
Calls Offered / Calls Forecasted
Handled to Forecast %
Definition: The percentage of calls actually handled compared to the forecasted call volume.
Example: If forecasted calls are 10,000 and handled calls are 9,200, handled-to-forecast is 92%.
Formula
Calls Handled / Calls Forecasted
AHT (Average Handle Time)
Definition: The average time an agent spends handling a customer interaction, including talk time, hold time, and after-call work.
Example: If agents spend 15,000 minutes handling 1,000 calls, AHT is 15 minutes.
Formula
(Total Talk Time + Total Hold Time + Total ACW Time) / Total Calls Answered
Loaded AHT
Definition: Average Handle Time adjusted to include outbound work in addition to inbound interactions.
Example: If outbound calls add extra handling time, loaded AHT gives a more accurate picture of workload.
Formula
(Talk time + Hold time + ACW + Outbound time) / Contacts handled
Chat Concurrency
Definition: The average number of chat sessions handled simultaneously by an agent.
Example: If an agent manages 2 chats at the same time, chat concurrency is 2.
Formula
Total Chat Time / Total Engage Time
Line Adherence
Definition: The extent to which agents meet required staffing levels at specific time intervals.
Example: If agents meet staffing requirements in 48 out of 60 intervals, line adherence is 80%.
Formula
Total Intervals Met / Total Intervals
Schedule Adherence
Definition: Measures how closely agents follow their assigned work schedules.
Example: If an agent follows schedule for 7.5 out of 8 hours, adherence is 93.75%.
Formula
(Adherent time) / (Scheduled time) × 100
Schedule Conformance
Definition: Compares actual login or working time against scheduled time.
Example: If an agent works 460 minutes against a scheduled 480 minutes, conformance is 95.8%.
Formula
(Working minutes) / (Scheduled minutes) × 100
Schedule Attainment
Definition: The percentage of agents who log in during a scheduled interval.
Example: If 45 out of 50 scheduled agents log in, schedule attainment is 90%.
Formula
(Actual agents logged in) / (Scheduled agents) × 100
Staff Time
Definition: Total time an agent is logged in, including handled, available, and auxiliary time.
Example: An agent logged in for 8 hours has 8 hours of staff time.
Formula
Total Handled Time + Available Time + Auxiliary Time
Production Time
Definition: Time spent by agents on productive activities including handling and being available.
Example: If an agent is productive for 6.5 hours out of 8, production time is 6.5 hours.
Formula
Total Handled Time + Available Time
Productive Time
Definition: Time spent actively handling customer interactions.
Example: If an agent talks to customers for 5 hours, productive time is 5 hours.
Formula
Total Handled Time
Workload
Definition: The total amount of work expected to be handled in a period, calculated using forecasted volume and AHT.
Example: If forecasted calls are 5,000 and AHT is 6 minutes, workload is 30,000 minutes.
Formula
Forecasted Calls × AHT
Net Headcount (100% Occupancy)
Definition: Minimum number of agents required assuming full occupancy.
Example: If workload is 1,000 hours and each agent provides 8 hours, net headcount is 125 agents.
Formula
Workload / (Shift Length × Working Days)
Net Headcount (Customized Occupancy)
Definition: Required agents considering a realistic occupancy level.
Example: At 80% occupancy, more agents are needed compared to 100% occupancy.
Formula
Workload / (Shift Length × Working Days × Occupancy)
Gross Headcount
Definition: The total number of agents required to maintain the desired net headcount after accounting for shrinkage and attrition.
Example: If net headcount is 100 and shrinkage is 25%, gross headcount becomes ~133.
Formula
Net Headcount / ((1 − Shrinkage) × (1 − Attrition))
Model Occupancy
Definition: The projected occupancy level based on simulated schedules and Erlang calculations.
Example: Used in Erlang models to validate staffing efficiency.
Formula
Forecasted Productive Time / Scheduled Hours
Scheduled Inflexibility
Definition: Measures overstaffing caused by rigid scheduling constraints.
Example: Fixed shifts may cause excess staff during low volume periods.
Formula
(Scheduled Staff − Required Staff) / Required Staff
Scheduled Efficiency
Definition: Indicates how well schedules match workload while minimizing waste.
Example: Higher efficiency means better alignment between demand and staffing.
Formula
1 − ((Net Scheduled Staff / Required Staff) × Scheduled Inflexibility)
Forecast Accuracy
Definition: Measures how close the forecasted volume is to actual volume.
Example: If forecast was 10,000 calls and actual was 9,500, accuracy is 95%.
Formula
1 − (Variance / Forecast Calls)
Training Throughput
Definition: Measures effectiveness of training by comparing certified vs started trainees.
Example: If 80 out of 100 trainees get certified, throughput is 80%.
Formula
Headcount Certified / Headcount Appeared for Certification
EPH (Emails Per Hour)
Definition: The number of emails handled by an agent per hour.
Example: If an agent handles 40 emails in 4 hours, EPH is 10.
Formula
Contacts handled / (Production time − Idle time) or EPH = 1 / AHT
FTE (Full Time Equivalent)
Definition: Represents the number of full-time agents required based on workload.
Example: If workload equals 80 productive hours per day, FTE requirement is 10 agents.
Formula
Total Workload Hours / Working Hours per Agent