Here are my ideas:
1. Perform Gage R & R on the tests that are most difficult to pass. You may be able to reduce the %Study Variation associated with the test method or see if training is warranted.
2. Do a Lean project on lab efficiency. This could include sample turn-around time, sample handling (do samples get lost or expire?). Do you have the correct number of analysts and how much of their time is spent on value-added activities.
3. Look at sampling methods. Are you collecting the right number of samples at the right frequency (based on variation).
You will probably have to collaborate with colleagues if these topics are outside of your area of responsibility. You should be doing this anyway.
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