MES, MOM & Shop-Floor Data Systems worked example

Line Status Accuracy at 68% target accuracy rate: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop target accuracy rate to 68%, then walk the calculation through step by step. Measure how accurately the MES reflects actual line status (running, down, idle, changeover) by comparing system state against spot-checks on the floor.

The inputs for this scenario

  • Status checks matching actual state: 87 checks (held at the documented default)
  • Total status spot-checks performed: 100 checks (held at the documented default)
  • Target accuracy rate: 68 % (the input this scenario stresses; the baseline uses 95)

Working through the calculation

  • The calculation starts from the formula this tool documents: Line status accuracy = (matching checks / total spot-checks) x 100.
  • Line status accuracy rate works out to 87 % at these inputs, and this is the headline figure for the scenario.
  • Gap to accuracy target works out to -19 points at these inputs.
  • Matching status checks works out to 87 count at these inputs.
  • Total spot-checks performed works out to 100 count at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target accuracy rate sits at 95% and the headline result is 87 %, this scenario lands almost exactly on the baseline at 87 %.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to target accuracy rate, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. Accuracy depends entirely on a representative, unbiased sample — checking only during steady running overstates accuracy, since most errors occur during fast state transitions like micro-stops.

Results at a glance

  • Line status accuracy rate: 87 % (headline result)
  • Gap to accuracy target: -19 points
  • Matching status checks: 87 count
  • Total spot-checks performed: 100 count

Run it with your numbers

  • To rerun this with your own numbers, open the live Line Status Accuracy calculator, set target accuracy rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.