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