Contact Center Solutions Featured Article

Predictive Dialers: A Grid-based Approach

February 21, 2008

Predictive Dialers have long been the object of heated debates between telemarketers and call centers on one side (who love the technology for its productivity gains) and consumers on the other side (who detest it for the dead air and silent calls the technology bring with it). It is interesting to note that both the FCC and the FTC have enacted tough regulation to protect consumers by requiring strict monitoring and reporting of call abandonment in telemarketing campaigns and call center organizations.

Every year the call center industry spends thousands of dollars buying expensive equipment or online packages with predictive dialing capabilities. The called party experience generated by such dialers is poor and has pretty much restricted the technology for use in B2C calling—preferably cold calling. In addition, the rate of innovation and technology improvements has been relatively slow in this specific space and in the call center industry generally.

While call center telephony may have failed to evolve at a rapid pace, other forms of telephony that may not seem related to it have continued to morph at a fast pace. For example, PC-based telephony software has improved by leaps and bounds over the last few years. Softphone technology has leveraged generic PC hardware to boost call quality to new levels. Sophisticated applications like voice analysis and conferencing are supported in virtually all softphone applications.

Voice over IP (VoIP) technology has also become fairly ubiquitous and standardized with a large number of service providers and vendors getting involved. It is now possible to combine these two technologies with some popular PC technologies like Grids and Peer-to-Peer computing to create “telephony grids.” A telephony grid is a distributed, PC-based phone network that can perform coordinated dialing, IVR and voice analysis, or store voicemail without requiring centralized servers. While this may only seem to be a technology shift there are some other benefits as well. Before diving into those, let’s first try to explore the current state of predictive dialers.

How Predictive Dialers Work

A predictive dialer essentially attempts to dial calls ahead of agents becoming free. By dialing ahead, it tries to save on the dialing time and detect errors or answering machines. One may be led to think that the dialer can literally scan a whole list even before the first call is handed off to an agent. However, the dialer may not dial too many calls ahead of time since regulations limit the amount of dead time in beginning of calls or the abandoned rate.

Wikipedia defines “predictive dialer” as follows: A predictive dialer uses a variety of algorithms to predict both the availability of agents and called party answerers, adjusting the calling process to the number of agents it predicts will be available when the calls it places are expected to be answered. The predictive dialer monitors the answers to the calls it places, detecting how the calls it makes are answered. It discards unanswered calls, busy numbers, disconnected lines, answers from fax machines, answering machines and similar automated services, and only connects calls answered by people to waiting sales representatives. Thus, it frees agents from the task of manually dialing telephone numbers and subsequently listening to ring tones, unanswered or unsuccessful calls.

Note that predictive dialing does not work for everybody. While it boosts the average talk time by more than 50 percent compared to simple automatic dialing, these numbers apply only to large call centers and low-quality lists. Why is that so? Because this form of dialing depends on statistical calculations of a higher number of agents or more calls which fail to connect to live people; that increases the chances of the dialer’s predictions turning out to be accurate.

There are two popular forms of dialers: the on-premise dialer (or “box”) and the hosted dialer (or “service”). In either case the dialer uses expensive hardware and telephony back ends to optimize high volume calling needs. On-premise dialers are relatively more expensive, but since the software runs on premise, call handoffs between the dialer and the agents are quick. There are less of bad experiences on the called party side and overall performance is good. A good deal of staff is required to run and maintain the dialer system as well.

A hosted dialer, on the other hand, is much cheaper to use and requires no technical staff at the customer location to be managed. Most hosted dialers store the data in secure servers. However, data is still virtualized and may lead to loss of flexibility and restrictions on how it is handled. Hosted solutions should be carefully evaluated with regards to their security capabilities. Since the dialer is remote to the agents in a hosted system, the call handoff times can be relatively higher resulting in poor customer experiences. Hosted dialers have one big advantage over on-premise dialers: home agents. If a call center’s model allows for home agents, that becomes key to solving the low skill and huge turnover challenges most call centers suffer on the human resource front.

How Telephony Grids Work

A telephony grid uses software which can run on off-the-shelf PCs that are inexpensive to buy and maintain. A distributed coordination algorithm is used to coordinate the call handling process on the PCs. A telephony grid can run on a single PC or a large network of PCs on the internet and is managed from a single point. This ability to coordinate and manage the system is what distinguishes it from Peer-to-Peer telephony. Grid software is also specially designed to operate in an environment where other PC applications are running without adversely affecting their performance. Thus in a call center environment, agents are assumed to carry on with typical tasks on their PCs like database access, word processing and browsing while the same PC is participating in the telephony grid of the call center.

Grids nodes are of three kinds based on the bandwidth available on the link which connects the node to the grid. A node which has around 40 kbps of symmetric bandwidth on its connecting link is an active node. A node with less than 40 kbps of symmetric bandwidth is a passive node. Nodes which are connected with links exceeding 120 kbps of bandwidth are contributor nodes. Active nodes and contributor nodes collectively create VoIP calls for the system. Passive nodes can also make and receive calls for the system using regular phone lines. A low bandwidth link provides the necessary coordination with the rest of the system.

Telephony Grids can be used for almost all call center applications, especially IVR and Predictive Dialers. Since the complete software application runs in enterprise premises, they offer the same efficiency and benefits of on premise solutions. For example, customer perception of dead air is minimal since call handoffs are done locally between nodes. They are also much cheaper and scaleable than hosted systems since most of the heavy lifting of data and calling is done on PCs on customer premises with very little server or network involvement. Management of such systems can be offered in a hosted manner to simplify staffing requirements of call centers.


Medhavi Bhatia is the CTO at 3CLogic. He maintains two blogs: and
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