Operational Indicators – Service Levels, ASA & Occupancy Rate, guide customer experience workforce management and CX leadership.

By: Turaj Seyrafiaan

In the last Indicators post, we discussed one of the most important operational indicators: Average Handle Time or AHT. In this issue, we continue with other operational indicators dealing with the efficiency of the center, i.e. “Service Level”, “Average Speed of Answer (ASA)” and “Occupancy Rate”. Although each indicator provides different information, they are inter-related and must be treated as a single group.

Service Level

Service level, the most commonly used center metric – is defined as the percentage of contacts that are answered within a specified target time threshold. It is presented by two numbers such as “70 – 30”.

1) The first number indicates the percentage of the calls

2) The second number indicates the target time threshold in Seconds. The threshold is measured from the time that the calls arrive in the queue and does not include any time prior to that (e.g. time spent by the customers navigating the IVR menu).

A 70 – 30 service level, means 70% of calls were answered within 30 Seconds.

In practice, Call Centers set their overall target (both percentage of calls and the threshold) in conjunction with their Work Force Management (WFM) process in order to calculate their staff requirements and scheduling (more on that in later sections). A higher Service Level means faster service (answering the call) for customers. The actual Service Level – achieved percentages within that set threshold – is then reported on a daily/ weekly/ monthly and annual report.

Service Level can be manipulated by an unscrupulous manager through reducing or ‘choking’ the incoming calls and by reducing lines etc. Remember service level is a measure of the percentage of calls answered within a defined timeframe measured over a period of time, so you must ensure that the period of time over which service level is measured is reasonable. When working with service level as an average, the larger period of time over which it is measured the more periods that can fall below the target. For example, service level measured over a 24-hour period can be missed for periods during the day and made up for during the evening or overnight period. Measured over a week could mean missing the service level Monday through Wednesday and making up the service level over the balance of the week.

A third factor or metric is often added to Service Level: that is Abandoned Calls. Abandoned Calls can be defined as the percentage of callers who elect to hang up, or abandon while waiting in the queue before an agent answers the call. A service level of 80/20/<3 would be answering 80% of the incoming calls answered within 20 seconds, with less than 3% of calls being abandoned.

Average Speed of Answer (ASA)

While Service Level indicates the percentage of calls that were answered within the set threshold, it does not provide any information regarding the remaining calls! In practice, even when reaching the target Service Level, it is possible for a number of calls to spend a significant (and unacceptable) amount of time in the queue without impacting the Service Level. For this reason, it is important to look at this indicator that represents 100% of the callers. Average Speed of Answer (ASA) is the average wait time (in the queue) for all the calls answered, in seconds. Obviously, a lower Service Level (lower percentage of calls or longer threshold) produces a longer ASA. Combined with the Service Level, ASA provides a complete picture of the flow of the incoming calls. For example, an ASA of 18 seconds over 100% of calls received along with the Service Level attained of 80-85% (at 20 Seconds threshold) indicates a significant delay in answering calls beyond the first 20 seconds and therefore very poor service for the remaining 15-20% of customers). This is the effect of a long tail of outliers in any set of observations. This outlier effect on the customers’ view of the service is not intuitively obvious to many, both inside or outside the Contact Center industry.

Occupancy Rate

Although not related to the customer wait time, Occupancy Rate is very much part of the WFM process and related to the Service Level. Occupancy Rate indicates the percentage of logged-in time that agents are occupied, performing call center activities (talking to customers and/or performing after-call tasks). The inverse (100% minus Occupancy Rate) is the amount of time that agents are waiting for calls to arrive, also called Availability or Idle time.

A higher Occupancy Rate indicates a more efficient Call Center in terms of WFM and labor costs, however, Occupancy Rates in the high 90% range also indicate extreme workload on the agents – leading to fatigue, poor performance and eventually high turnover. This can also lower Service Level causing longer wait time for customers.

A Low Occupancy Rate could indicate poor planning and/or scheduling (too many agents waiting for calls to arrive). Low occupancy can also lead to poor morale and agent dissatisfaction.

The art of the Work Force Management process is to create a balance between the Service Level and the Occupancy Rate. Practice shows that for most centers an Occupancy Rate of between 75 to 85 percent is optimal.

Target Service Level

Many Contact Center managers assume that a target Service Level of 80 -20 is the industry standard and therefore use that as their own target. While this may be the most common service level for customer service Call Centers, the fact is that there is no industry standard for the Service Level. Each center must set its’ own target primarily based on customer expectations as well as budgetary and staffing limitations. While there are centers that feel a 90 -10 service level (90 percent of callers are answered within 10 Seconds) is not good enough, there are other centers that can reach an excellent customer satisfaction with 80 – 30 or even 70 – 30, although setting the threshold target beyond 30 seconds is not recommended. Keep in mind that this is time in the queue only and a customer may have already spent additional time in the IVR.

Industries with Higher Service Level Standards

Centers such as 911 or emergency set their standards as 100 – 3. If you are calling with an emergency then that level of service is appropriate.

Similarly, technical support centers often have target service level wait times of 3 to 5 minutes for free support. Once again, this is appropriate.

Each center must define what is appropriate for their center and their customers. Your service level targets also have to be reasonable. There is no sense setting a target that is clearly not achievable. Targets must be reasonable and when they are not met the center manager must report on why the targets were not met!

Work Force Management (WFM)

We need to understand how these indicators are used in conjunction with the WFM process. In brief, WFM is a series of activities related to forecasting call/contact volumes -scheduling required and appropriate staff.
Part of this process involves using Erlang formulas to calculate the required number of staff for a given forecasted call volume. The main equation (Erlang “C”) has 4 variables;

1) Call Volume,2) AHT (total of Average Talk Time and After Call Work)
3) Target Service Level
4) number of Agents

The equation requires 3 out of 4 specific inputs while calculating the 4th one. A user provides volume based on forecasting, AHT based on history and target Service Level based on the center’s long-term strategy, to calculate the required number of agents for any given staffing period. If, the number of staff is fixed (or has a limited range) the equation can be used to calculate the potential for the Service Level.

Erlang “C” Equation can also provide theoretical ASA and Occupancy Rate based on the provided inputs. Using a simple Erlang Calculator, one can experiment in determining what should be the appropriate target Service Level.

But, WFM is more than simply employing Erlang to determine your agents for a day-part. You must also schedule lunches, breaks, scheduled training, and vacations, and deal with the 2-3% of staff that will not show up for their shift. If you do not account for all of the above in your schedule then you will not have the correct number of agents available when the forecasted calls are received and the center will miss the service level target.

Improving Operational Results

How does a center improve results as they relate to the Service Level? The most effective approach is a robust WFM process. A competent WFM approach can provide the best and most achievable solution for the forecasted call volume. A well-developed schedule ensures the adequate number of agents are available for any given period matching the requirements for achieving the target Service Level. That said, we must realize that nothing within a scheduling process can compensate for poor forecasting/planning or unrealistic AHT or Service Level expectations!

While a detailed schedule relies on an accurate forecast to deliver the number of calls, it is up to the agents and management to follow the schedule and be available for those incoming calls as predicted. Hence the emphasis on “Adherence” to schedule but that is another story altogether.

Lastly, even with a great forecast and schedule, Call Centers must be capable of tactical adjustments to their operations during the day as the incoming call pattern for the day unfolds. An experienced WFM manager with a focus on “Intra-Day” adjustments can significantly and positively influence the final outcome for the Service Level and the Occupancy Rate.

A little-known tip is to use the doubling point to know when, where and what adjustments to make. This is the point of any day where half the calls have arrived. This is derived historical norms for each day of the week. What point of each day has half the volume arrived? Are there the right agents doing the right activities? What adjustments can the center management make?

Balancing Act

Service Level, ASA and Occupancy Rate all provide a view of how efficiently a center is operating. While Service Level and ASA focus on the wait times for the customers, Occupancy Rate is an indication of the wait time for the agents.An experienced WFM manager or Contact Center manager can provide a balance between needs of the customers (i.e. better Service Level) and needs of the organization (i.e. higher Occupancy Rate) while staying within the boundaries of the center’s limitations such as operating budget and resources.

We will discuss later the financial indicators such as Cost per Call (or Cost per Minute) and overall operating expenses.

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This content was originally created in 2010 and was updated Mar 19, 2018