RCA Step 3: Root Cause Determination
As explained in the Data Analysis section, the bulk of the RCA process is an iterative application of the data analysis and root cause determination steps. In many ways the problem statement and root cause analysis steps are identical - and the output is identical in that the output of the root cause determination step is another problem statement - although a more refined and specific problem statement.
Although the words root cause determination may imply that the goal is to find the root cause - actually this is only true on the last iteration. Until that iteration the goal is to slightly refine the previous problem statement until the root cause becomes obvious.
In some literature this is called the "why" phase - each iteration adds a "why" to the problem statement.
Using the example from the Data Analysis section, the intial problem statement stated that 50% of the product was arriving at the customer's dock damaged (numbers are changed but are relatively correct plus the problem statement is not in the proper format).
Why is 50% of the product arriving damaged? Because 50% of the product is damaged by the time it is loaded in the container.
Why is ths level of damage seen in the containers? Because prior to loading 40% of the product is alreadly damaged and 10% is damaged during loading of the container.
At this point the team determined that there were at least two problems. One was damage incurred during loading and the other problem was damage occuring prior to loading.
In solving the loading problem the team found that 100% of the loading damage was the result of scraping the bottom of the package on the container edge.
In the end it was determined that the real root cause was that the container door was only 2 inches larger than the package and the fortruck drivers had clear view of the top of the package but could not see the bottom. In addition, they could notfeel when the bottom was scraped causing damage. Therefore the truck drivers focussed on not damaging the top of the package. As a result they unknowingly damaged the bottoms. It was found that for no extra cost, the facility could request containers with doors that were 6 inches larger than the packages and when they did so, this source of damage was virtually eliminated.
The other sources of damage (4 were found) were identified in a simlar manner.
Thus rau=ises aother important characteristic of root cause analysis: in many cases one may not find a single root cause - there may be several root causes
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