PM Compliance and Schedule Compliance are maintenance measures that answer different questions.
They are often confused because both relate to whether planned work was completed on time.
The distinction matters.
PM Compliance asks whether preventive work was completed in its allowed window
A common form is:
PM Compliance = PM tasks completed within the defined compliance window ÷ PM tasks due × 100%
The compliance window should be defined by the organization.
For example, a monthly PM may allow completion within a controlled early/late tolerance.
The metric should not be manipulated by closing overdue work orders without doing the work.
Planned Maintenance provides the broader system for defining recurring preventive tasks.
Schedule Compliance asks whether scheduled work was executed as scheduled
A common form is:
Schedule Compliance = scheduled work completed as scheduled ÷ total scheduled work × 100%
The denominator should reflect work that was deliberately placed on the approved schedule.
Maintenance Planning and Scheduling distinguishes planned work from scheduled work and is essential for interpreting this metric correctly.
The two metrics diagnose different problems
Low PM Compliance may indicate:
- preventive work is being deferred;
- PM frequency is unrealistic;
- resources are insufficient;
- emergency work is displacing PMs.
Low Schedule Compliance may indicate:
- the weekly schedule is unstable;
- work is not ready;
- operations access is unavailable;
- emergency work is consuming capacity;
- priorities change frequently.
A site can have high PM Compliance but poor Schedule Compliance if PMs are completed eventually but not when planned.
Define the denominator carefully
Metric definitions should be stable.
Questions include:
- Are cancelled work orders excluded?
- How are emergency jobs treated?
- What counts as completed?
- What is the PM tolerance window?
- How are partial jobs handled?
Without a clear operational definition, two departments may report the same KPI differently.
Use the metric to improve the system
A KPI should trigger learning.
For example, if Schedule Compliance is low, ask whether:
- work packages are complete;
- parts are available;
- permits are ready;
- the labor estimate is realistic;
- operations agreed to equipment access.
Maintenance Backlog Management helps maintain enough ready work for reliable scheduling.
Avoid gaming PM Compliance
A team may improve the number without improving reliability by:
- extending due dates;
- cancelling overdue PMs;
- changing frequencies without technical justification;
- completing tasks superficially.
The metric should reflect real execution of technically necessary work.
Connect compliance to reliability outcomes
High compliance is useful only if the maintenance strategy is appropriate.
A site can achieve 100% PM Compliance while repeatedly performing low-value tasks.
PM Optimization helps review preventive work for effectiveness, interval, failure mode, and value.
Execution discipline and strategy quality must work together.
Segment when needed
Useful views may include:
- critical assets;
- production area;
- maintenance trade;
- work type;
- reason for noncompliance.
The purpose is diagnosis, not metric overload.
Common mistakes
Using PM Compliance and Schedule Compliance interchangeably, changing the denominator month to month, counting closed work as completed work without verification, rewarding compliance without examining reliability results, and ignoring the reasons scheduled work was displaced are common mistakes.
Practical sequence
- define PM Compliance precisely.
- define Schedule Compliance precisely.
- establish consistent denominators.
- define allowed PM windows.
- measure execution honestly.
- categorize reasons for misses.
- correct planning and access barriers.
- protect appropriate preventive work.
- review whether PM tasks are technically effective.
- connect compliance trends with reliability results.
The practical lesson
PM Compliance measures preventive-work timing.
Schedule Compliance measures schedule execution.
They are related, but they diagnose different parts of the maintenance management system.