Industrial Cybersecurity & OT Risk worked example

Patch Compliance Rate at 99% target patch compliance: a worked example

This scenario runs the patch compliance rate calculation on the strong side: 99% target patch compliance, with every other input held at its documented default. Use it when reviewing patch backlog across HMIs, servers, engineering workstations, historians, and vendor supported OT endpoints.

The inputs for this scenario

  • OT assets patched to approved baseline: 112 assets (unchanged)
  • Total OT assets eligible for patching: 150 assets (unchanged)
  • Target patch compliance: 99 % (raised for this scenario; the documented default is 90)

Working through the calculation

  • Applying the documented formula (Patch compliance rate = OT assets patched to approved baseline ÷ total OT assets eligible for patching × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 74.67 % for ot patch compliance rate, the number this scenario is built around.
  • At this operating point the engine returns 24.33 points for patch compliance gap to target.
  • At this operating point the engine returns 112 count for ot assets patched to approved baseline.
  • At this operating point the engine returns 150 count for total ot assets eligible for patching.

How this compares with the baseline

  • Against the tool's baseline example, where target patch compliance sits at 90% and the headline result is 74.67 %, this scenario lands almost exactly on the baseline at 74.67 %.
  • Use it for monthly OT security reporting, audit and insurance evidence packages, and after each maintenance window to confirm the patch cycle moved the needle. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • OT patch compliance rate: 74.67 % (headline result)
  • Patch compliance gap to target: 24.33 points
  • OT assets patched to approved baseline: 112 count
  • Total OT assets eligible for patching: 150 count

Run it with your numbers

  • Every input above is editable in the live Patch Compliance Rate calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.