Contact centre routing strategy and WFM

Staffing calculation impact

Cannot use a single Erlang C calculation for total volume. Each skill group must be staffed as a semi-independent queue with its own Erlang model. The combined staffing requirement is higher than a fully blended equivalent because smaller pools are less efficient. Staffing calculations must account for multi-skill agents who bridge queues — their contribution must be allocated across the queues they serve.

Schedule impact

Schedules must ensure each skill group is covered at every interval. An agent scheduled to start at 09:00 who is the only Spanish-qualified agent on the early shift creates a single-point-of-failure risk. Skill coverage must be checked at interval level, not just total headcount level.

Staffing calculation impact

Total headcount requirement is driven by the priority contact volume against the priority SL target. Standard contacts receive whatever capacity remains after priority demand is served. The WFM function must confirm that enough agents are staffed to serve priority demand at target SL before assessing what SL standard contacts will receive — standard contacts are a residual, not a first-order constraint.

Schedule impact

No specific scheduling change beyond the staffing requirement driven by priority SL targets. However, if standard contacts have a contractual SL target (e.g. outsourced BPO environment), the schedule must be built to serve both priority and standard SL targets simultaneously — which requires a more complex capacity calculation.

Staffing calculation impact

Overflow routing does not reduce the total staffing requirement — it redistributes the shortfall from the primary team to the overflow destination. The primary team must still be staffed to handle the baseline volume; overflow handles the excess. If overflow is routinely triggered, it indicates the primary team is chronically understaffed, not that overflow routing is working as designed.

Schedule impact

The overflow destination must be staffed with available capacity at the same intervals where the primary team is most likely to overflow — which are typically the same peak intervals where the overflow destination also has its own peak demand. WFM must coordinate with the overflow destination to ensure they have capacity available when it is needed, not just that overflow routing is technically enabled.

Staffing calculation impact

Preferred-agent routing creates artificial demand concentration on specific agents. If a customer always waits for their preferred agent rather than accepting any available agent, the effective capacity of the queue is reduced. The WFM staffing model must account for the proportion of contacts that will wait for a preferred agent — which increases average wait time and AHT (returning callers may be more complex) relative to a non-PAR environment.

Schedule impact

Scheduling preferred agents off the phone (training, meetings, annual leave) creates predictable customer-experience gaps if their customers call during that window. The WFM team should flag PAR agents' planned absence to the relevant team leader so that affected customers can be pre-notified or temporarily routed to a nominated backup.