Workforce Management for Skills-Based Routing: The Need for Integrated Simulation
By Paul Leamon, IEX Corporation

Skills-based routing allows contact centers to route different types of calls - for example sales, service, and payment processing - to the agents who have the skill necessary for that call. When agents are cross-trained, so that some or all have more than one skill, skills-based routing can increase the amount of time agents spend handling calls--offering significant cost savings and improved service levels without additional staff.

Implementing skills-based routing adds new workforce management challenges for contact centers. The process of creating accurate forecasts and developing efficient schedules for agents in centers that handle only one call type is well understood; achieving the same goals when the center handles different types of calls is much more complex.

Workforce management systems employ several different approaches to forecasting and scheduling to address the unique complexities of skills-based routing.

Forecasting Using Erlang C

In a center that is not using skills-based call routing, agent requirements can be derived through simple mathematic calculations. Forecasts of call volume and average handling time (AHT) over the desired time intervals and service level goals can be input into an industry-standard Erlang C formula that calculates the number of agents needed for each time interval.

However, using a mathematical formula by itself to calculate agent requirements does not yield optimal results in skills-based routing environments. Mathematical formulas like Erlang C usually result in overstaffing when applied to skills-based routing environments because they do not account for sophisticated ACD call routing logic and efficiencies from multiskilled agents. When agents have multiple skills, there is a greater likelihood that an agent with the necessary skill for an incoming call will be available, so fewer agents overall are required to manage the same number of calls at the same service level.

Forecasting Using Multi-Server Queuing

Another mathematical forecasting method uses multi-server queuing formulas to calculate agent requirements. This approach assumes agents within agent groups possess identical skills, and provides an approximation of the multiskill efficiency gained by skills-based call routing. Multiserver queuing formulas cannot be used to forecast agent requirements when agents are assigned to individual skills and skill levels, however. The formulas assume that calls are routed to separate queues for each agent group or to a common queue for all agent groups.

The assumptions in multi-server queuing formulas are rarely true in the real world. In most skills-based routing environments, calls may be queued to agent groups simultaneously or based on conditional rules. Agents are also typically assigned different skill priority levels, which further affect call routing.

Skill Scheduling for a Single Call Type at a Time

Once a forecast has been generated, the workforce management system must schedule agents to meet the forecasted agent requirements. Creating schedules in skills-based routing centers is significantly more complex than non-skills centers because the workforce management system is no longer just scheduling enough total agents to meet requirements for one call type, but must schedule the right combination of agents to meet requirements for each call type, and still take contact center work rules into account.

The most simplistic scheduling approach assigns multiskilled agents to one call type for each scheduling interval. For example, agents with sales and service skills might be scheduled for sales calls from 8:00 am to noon and service calls from 1:00 pm to 5:00 pm. Scheduling agents to specific call types for each interval results in low quality schedules because the schedules either sacrifice the efficiencies of skills-based routing or do not match the actual ACD routing rules.

Schedule from Most- to Least-Skilled Agents

Another method schedules the agents with the most skills first. This approach makes the assumption that skills are related and that an agent with Skill 3 can also handle call types based on Skill 2 and Skill 1:

•  First, the system schedules the most skilled agents (agents with Skills 1, 2 and 3) against
   the call type forecast requirements that use Skill 3.
•  Next, requirements of call types that use Skill 2 are added to those that use Skill 3, the
   system applies a factor to decrease the combined requirements, and schedules agents with
   Skills 1 and 2.
•  Finally, the requirements of call types that use Skill 1 are added to those that use Skills 2
   and 3, and the system again decreases the combined requirements and schedules agents
   with Skill 1.

This approach cannot be used when agents have individual, non-related skills - such as language- and are not uniformly trained to be in one of a few different skill sets. In most contact centers with skills-based routing, a skill is not related or dependent on another skill and may be assigned to agents based not only on training but also on actual performance. Most importantly, the method of scheduling from most-skilled to least-skilled agents does not consider routing rules that affect agent availability such as conditional queuing or queuing to backup skills.

Forecasting and Scheduling Through Integrated Simulation

The key flaw with the forecasting and scheduling methods described previously is that they do not take the actual contact center's ACD routing rules into account. They also do not resolve the circular challenge of forecasting and scheduling: forecasted agent requirements are dependent on individual agent skills and agent schedules, which in turn are dependent on forecasted requirements and the way that calls will actually be routed.

The solution to achieve both accurate forecasts and efficient agent schedules is to integrate simulation of ACD routing into the forecasting and scheduling process. With an integrated simulator, agent requirements are calculated by call type, including the economies of scale gained by multiskilled agents, and agent availability by call type is also calculated. Schedules can be automatically generated against the agent requirements, and then analyzed after simulating ACD call routing - including network call routing for multisite centers.

Forecasts and schedules can then automatically be adjusted to improve results, and the process can automatically repeat until the best set of schedules and an accurate forecast have been determined. This solution accommodates the many variables and the complexity associated with a multiskill environment and automatically creates accurate forecasts and effective working schedules.

The simulator must also be fully integrated into the workforce management forecasting and scheduling cycle so that the iterative process of forecasting, scheduling and adjustments are automated. This process must be repeated multiple times to deliver high-quality forecasts and schedules. If the simulator is not integrated, the manual process of running simulations against schedules and adjusting the schedules and forecasts is prohibitively time-consuming and introduces opportunities for error.


About the Author:

Paul Leamon guides the product direction for TotalView, the award-winning workforce management system offered by IEX Corporation, a leading global provider of contact center workforce management and optimization technology that help customers improve planning, enhance performance, streamline tasks and integrate data. During his 15-years at IEX, Paul has consistently and successfully translated customer feedback into real-world solutions. Leamon is an inventor and co-inventor on several noteworthy workforce management patents that have been granted or are pending. Inquiries can be directed to paul.leamon@iex.com








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