Containers in heavy use may be washed more often and sustain more damage. Do not interpret the relationship between washing and damage before accounting for this shared use effect.
Measure the shared effect
Join period, use cycles, wash count and damage record by container ID. First calculate washes per cycle and damage per cycle.
Inspect the method separately
- If water or chemical records exist, compare them with instructions and shift records.
- For pressure-related damage, look for maintenance or observation records.
- For handling damage, check movement records to and from the wash line.
These records help investigate a possibility; they do not by themselves show washing caused damage.
Group by age and use
Compare containers of similar age and cycle count. Show container count and observation period in each group; one damaged item can shift a small group's rate.
Keep the hygiene step
A damage association is not a reason to reduce washing. Assess a wash-method hypothesis against the model instructions and the authorized site hygiene and quality process.
Two rates rising together do not establish cause and effect; more cycles may increase both. Check cycles per container and when damage was first recorded.
Compare periods. Keep container group, cycle count, washes per cycle and damage per cycle side by side in the monthly table. Date any method change and interpret period differences using matched groups.
