Troubleshooting understanding root cause

In retrospect, what saved the day for me was my willingness to dig deep into theory, fully understand the root cause, and then try to solve it by putting pen to paper. So if you usually find yourself in the lab without a calculator or even pad of paper, you are probably heading down the well-trodden path of symptomatic troubleshooting toward certain disaster. 

Performance information for the incumbent resin was missing from the early parts of the decision-making process. The decision that the technical problem was the performance of the new resin was based on anecdotal information from plant personnel on the performance of the incumbent resin. That is, the plant personnel believed that the reject level for parts made from the incumbent resin was less than 5 %. A statistical analysis of the part defect rates was not performed. This lack of information early in the process allowed the plant manager to propose a poor technical solution without understanding the root cause for the defect. Later in the troubleshooting process, a statistical analysis of the defect rate indicated that the incumbent resin had a defect rate that was statistically equivalent to the new resin. 

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