Three Ways to Bring the Call Waiting Times Under Control




One of the more obvious changes that has occurred in the call center in the last 10 to 20 years is that the call center has taken on an operational role that is far different than before. In the past the call center for high technology companies was primarily used as a backup to technical support operation for service technicians in the field and on customer sites.

As products have become more and more reliable, the need for on-site service has been reduced. Whereas the most likely source of a problem 10 to 20 years ago was the hardware, the problems today are more likely the result of bugs in the software or conflicts between competing software instructions, either of which can be addressed without sending a service technician to the site.

The Challenges of the Inbound Call Center

Service managers who are responsible for field service are keenly aware of response time requirements. Many of their service contracts may have response time requirements in them that must be met. Thus, service managers have learned how to forecast manpower requirements to meet the response time demands of the customers. (This was first documented in the technical paper "Management Science Impact on Service Strategy" published in the November 1975 edition of Interfaces [Volume 6, Number 1, Part 2], which ultimately led Xerox to restructure its U.S. field service organization from one man territories to three person mini teams).

While it is very easy to see that a customer has called in to a service facility or call center requesting on site service, it is not as easy to see that a customer has called into the call center seeking assistance and is on hold awaiting service. It is even more difficult to see the number of customers who have called seeking assistance and who received only a busy signal or who became sufficiently frustrated with the waiting time for assistance that they finally hung up the phone.

There are a number of terms used to describe these situations. When the call center customer receives a busy signal indicating that all lines are busy, the customer has no alternative but to "balk," which means the customer must hang up and phone the call center back later. More than likely, the customer will try again at some future time. Call center customers who hang up after waiting on hold for period of time are said to have "reneged" out of the call center queue. The call center term for reneging is abandoned and is generally used by saying the percentage of abandoned calls is x percent. The percentage of customers receiving busy signals is directly related to the number of phone lines into the call center. Since each incoming line in the call center has a cost associated with it, companies try to find the minimum number of lines that will either eliminate the busy signals or reduce the percentage of busy signals to a level acceptable to management.

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An Example of Call Center Dollar Savings

Several years ago I was asked to review a call center for a service operation. The call center was used for technical support, and there were 800 number lines coming into the call center for each of the product lines being supported by the service organization. In fact, the company had 46,800 number lines coming into the call center. The question posed to me was how to manage the technical support personnel more efficiently (management wanted to raise the call center productivity in order to reduce the rate at which they were hiring support staff). I soon learned that each product line had its own phone lines and that they were not all routed through a central point. Thus, there were many times when one group would be very busy while other groups were idle.

When I suggested the a cross-training for technical support staff and the incoming phone lines combined through a central call distributor, there was some hesitancy until I made the calculation that showed they could reduce the number of incoming lines from 46 to 26. This savings on the reduced number of lines amounted to about $20,000 per month. After the reduction in the number of incoming phone lines, they improved call center productivity, reduced average call waiting time and generally had more satisfied customers. This was a simple case where knowledge of queuing was essential and no amount of "soft" management would have led to the answer.

Call Center Phone System Status

Most call center telecommunications software packages will measure the number of customers who renege and some will also measure the number of calls that received the busy signals. The number of calls on hold can now be easily posted in the call center with most telecommunications systems. The availability of the number of abandoned calls is generally not presented in real time but can be accessed from the telecommunication software.

The whole topic of queuing came about at the turn of the century as the result of a Danish telephone engineer by the name of Erlang when he was asked to design a telephone switch. In order to design the phone switch he asked how many lines to include in the design, but no one could answer him. Since he was a mathematically oriented engineer, he developed the basis of queuing theory by examining the mathematics of random events (phone calls) arriving of the telephone switch. What Erlang discovered is that phone calls arrive into a phone switch (read call center) according to the Poisson probability distribution.

The Poisson probability distribution is sometimes called an "amnesic" distribution since it appears to have no memory of what has happened in the post. Thus, the likelihood of a phone call arriving in the next minute is the about the same as it would be tomorrow or next week. Of course, the counter argument is that there seem to be more calls at certain times of the day, week, month or year. It is true there may be some changes in the arrival rate from one period to another (bank teller lines are not always busy); however, the key is that the arrival of the next call can never be predicted exactly. It is this aspect of the Poisson probability distribution that introduces potential error into any workload planning model.

The phone status display that is used with many call center telecommunications systems generally displays either the average time on hold or the current longest time on hold. In either case, the call center manager has the responsibility to react to the number and allocate the call center resources so that the call waiting times can be brought under "control."

Three Ways to Bring the Call Waiting Times Under Control

Firstly, you can increase the number of personnel on the phones (expensive and frowned upon by management).

Secondly, you can reduce the time spent on the phones between your personnel and the customer (preferred by management since if requires no additional resources).

A third way would be to assess the customer calls as they arrive such as using an automatic call director, and have automated responses for the simple requests and only use your personnel when necessary (also preferred by management for the same reasons). If the third method has already been implemented, the next step will most likely be the second method of reducing call times (in which the customer suffers).

Two Steps to Solution

The question is what should the call center manager do to maximize the performance of his call center when he is constantly faced with the flashing numbers on the board that indicate either one call on hold for a long time or the average hold time is above the response time goal of the operation. If the flashing numbers on the board that displays the call center phone queue statistics represents the longest hold time, it is not clear what impact more resources will do since the number may represent only one customer. If this is the measure you are currently using, I would suggest you change to the average hold time measurement instead.

Step I: Change to average hold time as the control parameter for the call center.

If you are using the average hold time as the measurement, the good news is that hold times can be quickly reduced with additional resources which do not have to be dedicated for an extended period of time. If you have ever noticed that the addition of one additional teller or checkout counter at the grocery store will quickly dissipate the queue, then you realize that the way to manage short-term queuing problems (excessive hold times) is to have a team of several people available to "open up" new channels.

Step 2: Use a Swat Team to reduce the call holding times.

Queues are very non linear. That means that the addition of a small amount of resource can have a very large impact on the call holding times. The key lesson from this article is to manage queues using the average hold times as the control parameter. When measurements indicate that hold times are higher than your objective, use a short-term "swat team" to get the queue under control.

First published on Call Center IQ.