Experts Are Only Human:
Expert troubleshooters, being human, suffer from human weaknesses. Here are two important ones, as related to Differential Diagnosis. These weaknesses were originally identified in the 1980s by studying how doctors diagnose, but they are still valid today, and they apply generally to experts in any complex domain.
“Availability”. An Expert can only recall an experience that is in his memory. If he himself has not experienced or learned of a problem, it will not be available to him for consideration during troubleshooting.
“Anchoring”. If a confident expert believes he knows the cause of a problem, there is a strong tendency to seize pre-maturely on that conclusion, in which case only supporting symptoms are acknowledged, and potentially conflicting symptoms are discounted as unimportant.
SpotLight is a powerful differential diagnosis engine that counters these weaknesses.
- It reasons upon a knowledgebase containing the collective experience of an entire community of users, thereby resolving the “availability” concern.
- All candidate solutions are kept in front of the user in a list ranked according to how each matches the reported symptoms as queried by SpotLight, thereby resolving the “anchoring” concern.
- Questions are asked to actively confirm or refute the leading hypothesis, further discouraging anchoring.
©2008 CaseBank Technologies Inc.
A maintenance technician, newly endorsed on an aircraft, is assigned for the first time to this type of aircraft. Although he is experienced on other aircraft, he still feels a certain uneasiness. Aircraft are very complex. There is no possible way for the new technician to become an instant expert. His classroom training gave him a basic understanding of how the aircraft systems work normally and how they are repaired, but he knows that these complex systems don't always fail in predictable ways. In many cases the manuals do not help – he must rely on the help of more experienced technicians who have seen such failures before. The only problem is that the technicians with that experience never seem to be around when needed.
When he arrives at the aircraft and checks the logbook, the technician finds that a critical system is failing intermittently. The pilots are complaining about unreliable operation. Following the troubleshooting manual does not isolate the fault. He tries swapping computers, but to no avail. Is it a software bug? An intermittent hardware component? A chafed wire somewhere in the miles of wiring that run through the aircraft? He suspects another technician may know the solution to this problem, but he has no idea where to find that person. He involves more and more people in the troubleshooting, and changes more and more parts. Soon, the Station Operations Center is screaming to get the aircraft back into operation. Finally, the solution is found. It turns out that there is a connector on the aft pressure bulkhead that has corroded, causing intermittent behavior in the system. Now the new technician knows something that very few other technicians know.
With CaseBank's guided diagnostic support, had this problem been seen before, the technician would have been quickly guided to it. If not, then this solution has already been captured by the software, and after expert validation, would be made available to the next technician who is presented with the problem.
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