WFM guideAbsence planning

Long-term sick management for WFM

Q: When should an absence be reclassified as long-term sick for WFM planning purposes?

For WFM planning purposes, an absence should be reclassified as long-term sick (LTS) when it has lasted more than 4 consecutive weeks with no confirmed return date. This is the point at which the absence: (1) transitions from short-term absence management (daily shrinkage, Bradford Factor, RTW interview) to a headcount event (the slot is unavailable and may need to be backfilled); (2) is typically handed from team leader day-to-day management to HR occupational health or case management; (3) becomes significant enough to require a discrete entry in the WFM headcount model rather than being absorbed in the aggregate shrinkage percentage. Some organisations use a shorter threshold (2 weeks), which is appropriate if the operation is running close to the net staffing requirement and even a brief LTS episode creates a staffing gap. Some use HR-defined thresholds (which may be 4 weeks or more for statutory sick pay classification purposes). WFM should use whichever threshold triggers a discrete WFM headcount model update — the trigger is operational, not administrative.

A long-term sick agent occupies a headcount slot without contributing any capacity. Short-term absence tools (Bradford Factor, daily shrinkage, RTW interviews) do not address this. WFM must treat LTS as a headcount event — tracked in the establishment model, with explicit decisions about backfill and phased return.

Short-term absence vs. long-term sick: different problems, different responses

Dimension	Short-term absence	Long-term sick (LTS)
Definition	Brief, unplanned absence — 1–5 days per episode	Continuous absence exceeding 4 weeks with no confirmed return
WFM model impact	Absorbed in the daily shrinkage % allowance	Additive to shrinkage — reduces effective operational headcount
Headcount slot	Agent occupies slot and returns; no net change	Agent occupies slot but contributes zero capacity for the LTS duration
WFM response tool	Shrinkage allowance in the staffing model; intraday adjustment	Headcount model update; backfill decision; phased return scheduling
Management tool	Bradford Factor, RTW interview, absence trigger	Occupational health referral, HR case management, ESA certification
Backfill question	No — short absence is absorbed by buffer/OT	Yes — if LTS count exceeds the headcount buffer, backfill is needed
Phased return planning	Not applicable	Required — WFM must schedule reduced hours / contact types

Three-phase WFM response to long-term sick absence

Phase 1: Bridge

Weeks 1–4 of continuous absence

WFM status

Absence tracked as short-term. Daily shrinkage model absorbs the gap. No headcount model update required.

Headcount model

No change. The agent occupies the headcount slot. The daily shrinkage allowance covers this period assuming the absence is not extended.

Decisions required

Confirm the return-to-work date with HR. If no return date is confirmed by week 3, flag to WFM Manager for reclassification review. Monitor whether the absence is affecting interval-level coverage — if the absent agent holds a specialist skill, check whether the skill queue is covered.

Phase 2: Stabilise

Weeks 4–16 of continuous absence

WFM status

Reclassified as long-term sick. Discrete entry added to the headcount model. Headcount deficit calculated and compared to buffer capacity.

Headcount model

The agent's slot is flagged as temporarily unavailable in the headcount plan. The deficit is quantified: if the net staffing requirement is 100 agents and 3 are LTS, the effective operational headcount is 97. If the buffer (above net staffing) is 5, the operation can absorb 2 LTS without service impact. The third LTS agent creates a headcount shortfall requiring a response.

Decisions required

Is the shortfall within the buffer? If yes — monitor and review monthly. If the shortfall exceeds the buffer: (1) Is overtime available as a bridge measure? (2) Should a temporary agency agent or fixed-term contract be recruited? (3) Can the LTS period be covered by redeployment from another team? The decision depends on the expected duration of the absence and the operational impact.

Phase 3: Phased return

Variable — typically 2–8 weeks

WFM status

Return plan agreed with HR and Occupational Health. WFM schedules the phased return with reduced hours and contact exposure.

Headcount model

Phased return agents contribute partial capacity, not full capacity. A 50% phased return (e.g. 4 hours per day instead of 8) contributes 0.5 FTE to the operational headcount. Update the headcount model to reflect partial contribution rather than full availability. Avoid treating a phased return as a full return until the agent reaches their contracted hours.

Decisions required

Agree the phased return schedule with the agent and HR: which days, which hours, which contact types (returning agents may need to avoid high-complexity contacts initially). Schedule the phased return on lower-volume intervals or days to reduce pressure on the returning agent. Plan the exit from any temporary backfill when the phased return reaches full contracted hours.

When to trigger a backfill: the LTS backfill decision

Backfill trigger

LTS count exceeds headcount buffer

Required response

Backfill is required. The operation is running below the net staffing requirement — voluntary overtime and break adjustments are temporary fixes, not sustainable solutions. Initiate backfill recruitment or temp agency engagement.

Backfill trigger

LTS involves a specialist skill with no cross-trained cover

Required response

Backfill is required even if the overall headcount is within buffer. A single LTS agent in a small specialist queue (e.g. BSL-interpreted service, specialist regulatory advice) can eliminate the entire service capability. Do not wait for overall buffer to be exceeded.

Backfill trigger

LTS duration exceeds 12 weeks with no confirmed return date

Required response

Escalate the backfill decision to Operations Director regardless of current headcount buffer. An absence of this duration has a low probability of return within the scheduling horizon. The headcount plan must account for this slot being unavailable for the remainder of the planning year.

Backfill trigger

LTS agent holds WFM function knowledge (analyst or RTC)

Required response

Backfill is required immediately — even week 1. WFM function knowledge gaps produce downstream planning failures (missed forecasting cycles, incorrect schedules) that compound faster than a front-line agent absence.

Long-term sick WFM questions

When should an absence be reclassified as long-term sick for WFM planning purposes?

For WFM planning, reclassify as LTS when the absence has lasted more than 4 consecutive weeks with no confirmed return date. This is when: (1) the absence transitions from daily shrinkage management to a headcount event; (2) the slot must be flagged as unavailable in the headcount model; (3) a backfill decision may be required. Some operations use a 2-week threshold if they run close to the net staffing requirement. The operational trigger — not the HR or statutory sick pay classification — should drive the WFM reclassification decision.