Beyond Erlang-C: Embracing the Future of Staffing Algorithms

For decades, Erlang-C has been the cornerstone of call center staffing. It was revered for its mathematical precision in predicting the number of agents required to meet specific service levels based on forecasted workloads. Danish mathematician Agner Krarup Erlang’s contributions to telephone traffic theory, through his work spanning from 1909 to 1920, established the foundational application of probability theory to model and solve problems in telephone call distribution, loss, and waiting times. His work is recognized as marking the birth of queuing theory. Erlang’s methods were adopted a half-century later by the call center industry and used to balance customer wait times against the cost of staffing. It was a groundbreaking tool in an era where customer service operations were simpler and call volume predictions were less complex.

However, as call centers evolved into multifaceted contact centers, servicing not just voice calls but emails, chat, and social media inquiries, the once reliable Erlang-C model began to show its age. The formula’s inherent limitations—its assumption of steady call arrival rates and handling times and its inability to account for real-time variability—have rendered it increasingly obsolete in today’s dynamic customer service environment.

Beyond Erlang-C: Embracing the Future of Staffing Algorithms

In the dynamic world of call center management, the debate around staffing levels often revolves around the conventional wisdom of “net zero” staffing versus the perceived inefficiency of overstaffing. However, what if we reframed this debate?

We find a path forward by recognizing it not as “overstaffing” but as a strategic evolution toward a new staffing algorithm that leverages automation and real-time data to optimize workforce management. This approach intelligently accounts for the variability in call volumes and efficiently utilizes agent downtime for training, coaching, and other productive activities.

A New Paradigm in Staffing: The “New Net Line”

The traditional model of pre-scheduling non-call activities like training or coaching sessions weeks in advance is being challenged. With advanced automation tools, call centers can dynamically deliver these activities, drastically reducing the need for pre-scheduling and allowing for a more fluid and responsive staffing model.

This shift enables a “new net line” approach to staffing. Unlike traditional models that may be underprepared for volume spikes or inefficiently allocate resources, this new algorithm considers minimal interval variance, productive shrink factors, and daily absenteeism. By adding these factors as overhead to the line, call centers can calculate a staffing level precisely tuned to the day’s demands—not overstaffed but correctly staffed to handle both the natural variance and the necessary off-phone activities.

Emphasizing Real-time Adaptability

The cornerstone of this staffing philosophy is real-time automation, which adapts dynamically to the day’s needs. By monitoring call volume, queue depth, and service level in real-time, automation tools can identify opportunities to pull agents for training or coaching sessions during quieter periods, ensuring that these essential activities don’t detract from service levels. This approach maximizes operational efficiency and enhances agent engagement by breaking the monotony of continuous call handling with varied tasks.

The Economic and Strategic Benefits

Adopting this new staffing algorithm makes operational sense and is economically prudent. Research on forecasting models for call center arrivals indicates that understanding the variability in call volumes and the economic implications of staffing decisions is crucial. This new model aligns with these insights by optimizing staffing levels for service quality and cost efficiency.

Furthermore, this approach allows call centers to maintain high service levels without the excess costs traditionally associated with overstaffing. It represents a fundamental change in scheduling philosophy, where the focus shifts from mere volume handling to comprehensive workforce optimization.

The transition to a “new net line” staffing model is more than an operational shift; it’s a strategic reimagining of call center staffing. This model, far from being overstaffing, is a sophisticated response to the complexities of modern call center operations, blending the latest in automation technology with advanced forecasting methodologies. It acknowledges the realities of call volume variability and the need for continuous agent development, presenting a balanced, efficient, and economically viable approach to call center staffing.

This approach represents Level 3 of our Workforce Management Maturity Model at WFM Labs. In this new paradigm, call centers are prepared for the day’s challenges and poised to leverage every opportunity for growth and improvement.

Source: GWFM Research & Study