A weak route result alone does not blame the plate. Record preparation, layout, product start and lid events too.

A repeatable method

Match the run, plate batch, preparation record and conditions. On a repeat, hold other conditions steady and change one variable.

Shift control card

  • Reference condition
  • Plate batch
  • Single variable
  • Measurement result

When it repeats

Do not treat the result as proof of cause; add the comparison to technical review.