Abstract: If we reflect twenty plus years ago, we will recall that most of our quality
efforts were directed checking the quality of the final product in the
finishing and packaging stages.By
that point, if something was found defective, we would have to scrap the
entire run or lot of products produced.Then came the TPM initiatives that stressed “quality of process”
and we started to implement Statistical Process Controls (SPC) and
Statistical Quality Control (SQC).We
started to look at quality “during” the manufacturing process ensuring
that when the finished product came off the line, it was a quality product.Can we do the same with Root Cause Analysis (RCA)?
Taking the TPM
parallel described in the abstract above, let’s see if it applies to
non-manufacturing processes such as RCA.If asked, almost everyone will say they are doing Root Cause Analysis
(RCA).And to a large part,
they will be correct in their own minds.This is because of how they define RCA versus how the person asking
the question defines RCA.This
is like if we asked a sample population, “Do you live a healthy life?”The majority would reply with an emphatic YES.However, what does healthy mean to these people?To some if means we are alive, to others it means that we eat right
and exercise, to others it means that they are emotionally sound and to
others it may mean that they are content in their religious beliefs.
So how many ways
cannot someone interpret RCA?Some
believe it is 1) having the local expert provide us a solution, some believe
it is 2) brainstorming in a room and drawing conclusions from hearsay and
some believe in 3) the use of a disciplined thought process to seek true
root causes.
1)When the perceived expert provides a solution as an individual, we
are more apt trust their instincts, spend the money and their solution and
see if it works.Sometimes it
works, but more often that not, it does not work.Checking to see if the solution works is like checking
quality only at the finished product stage.It is too late if there is a defect found!
2)When teams are used to brainstorm using quality techniques such as
fishbone and/or 5 WHYS, they will usually draw conclusions based on majority
opinion.This means that
solutions tend to be implemented based on the consensus of the group’s
opinions, not on any factual basis where tests prove that these opinions are
correct.Again, we are checking
quality of the final product and not of the thought process that drew the
conclusions.
3)When teams use a disciplined RCA process that requires hypotheses to
be developed as to how something could occur, and then REQUIRE verification
with some essence of science as to whether it is true or not, then we are
employing quality of process!This
is because we are proving our hypotheses with facts rather than relying on
hearsay, assumptions and ignorance.
To demonstrate
these points, look at the following abbreviated example:
Figure 1.0 -
PROACT® RCA Disciplined Logic Tree
The above depicts
a disciplined thought process called PROACT®.Let’s think back to our RCA scenarios.If a critical pump were to fail, in some cases we would get our best
engineers to take a look at it.They
would do their engineering magic themselves and may conclude that a
different type of bearing (perhaps more heavy duty) should be in this
service.We would change out
the bearings with the new designed ones.Given the above scenario, would the problem go away?
What about if we
get our brainstorming teams together and everyone looks at the past
performance of the pump and its maintenance history and concludes that it is
a new lubricant they are using and that it should be changed.Under the above scenario, would the problem go away?
Utilizing the
disciplined approach above, we are going to have to have the bearing
reviewed by metallurgists.They will send back a report concluding (with science) that
there is evidence to support the presence of fatigue.We ask ourselves, How can fatigue occur on the bearing?We hypothesize that it can come from high vibration.We check our vibration monitoring records and conclude that there is
evidence of excessive vibration.How
can we have excessive vibration?We
hypothesize that it can come from imbalance, resonance and misalignment.We check our balance certifications and our vibration records
for resonance, and find not evidence to support that they are contributors.We ask the mechanic who aligned the pump to align it again and
observe his practices.From the
observation, we can conclude that he does not know how to properly align.
When we ask, Why
would he not align it properly?, we find that he was never trained in how to
align, he was using worn alignment tools and no procedure existed to follow.Now we know the REAL root causes, so we can develop solutions, that
when implemented, WILL WORK!!
Using the PROACT® disciplined process, we are utilizing quality of process versus quality of
product.The facts are leading
us to our conclusions, not hearsay.We
are not using “trial and error” solutions to see if they work.By the time we get to solutions, we know they will work because we
have maintained quality of the RCA process.
While the
undisciplined RCA approaches are attractive to organizations because they
produce a quick answer, it does not mean that the answer is correct.They are quick approaches because they lack proof that they are
correct.True RCA involves
taking the time to prove what we say, before we spend money to prove we are
wrong!!
