Backlog
Is backlog intrinsically a risk?
No: Backlog is a fact of life; risk arises only if it exceeds acceptable thresholds (e.g., >10% beyond key risk dates) or blocks critical work.
How to calculate 'ready backlog'?
Include only work orders that are approved, have a complete job plan (scope/parts/tools/skills/hours), parts in stock (or confirmed delivery), and are waiting to be scheduled.
Why not eliminate backlog?
Zero backlog equals idle technicians; optimal backlog stabilizes scheduling, maximizes wrench time, and buffers against emergency repairs.
What distinguishes backlog from overdue work?
Backlog is all 'good-to-go' open work (planned but not scheduled); Overdue is work past its original key risk date.
In CMMS and reliability engineering, maintenance backlog is the total volume of identified, approved, but uncompleted maintenance work (preventive, predictive, and corrective), quantified as crew-weeks (estimated labor hours of open work orders divided by weekly crew capacity).
On the shop floor, maintenance backlog serves as a strategic buffer, typically 2–4 weeks, to ensure technicians are consistently scheduled without stalling priority work. Planners use it to smooth workflow, balance capacity, and distinguish between 'ready backlog' (parts/scope ready) and 'planning backlog' (awaiting parts/engineering). This distinction helps optimize scheduling, maximize wrench time, and buffer against emergency repairs, preventing reactive chaos and financial inefficiency.
Zero backlog: Indicates under-identification of work, overstaffing, or missed PMs, leading to financial inefficiency and reactive chaos.
Unfiltered backlog: Including duplicates, completed-but-not-closed orders, or non-relevant tasks inflates metrics and misguides scheduling.
Mixing backlog types: Lumping planning, ready, and work-in-progress orders obscures true schedule readiness, causing planning errors and technician idle time.