Page 221 - Lean six sigma demystified

Chapter 5 Redu C ing d efe C t S with Six Sigm a 199

roads are now safer than ever before is because cars and roads are built better
than ever before. Antilock brakes, power steering, and crash protections all help
prevent fatalities.
To paraphrase a recent political campaign: It’s the car stupid!
The other main cause is bad driving habits: It’s the driver stupid!
What did this slow down in delivery of people and goods over the nation’s
highways cost? Although it’s almost impossible to connect all of the dots, the
stock market was down and interest rates soared. It did, however, create an
overnight market for CB radios and radar detectors.
What’s the new rising fatality cause? In 2008, distracted drivers talking or
texting on a cell phone killed 5,870 people and injured 515,000.Texting was a
factor in 200,000 crashes that year.

Emissions Testing

Similarly in 1995, Denver initiated an emissions-testing program to reduce
carbon monoxide and other emissions. The program costs $44 million per year,
but has only reduced emissions by 4%, far less than the 33% projected from the
initial data. Not surprisingly, 6.7% of the 833,122 cars tested in 2001 failed.
This is exactly three sigma.
One of the assumptions was that the owner would have their car fixed after it
failed. In reality, about 75% of the owners bring their car back through on another
day when the car passed because of variability in the testing process. In other
words, the testing process was barely at one sigma level (less than 30% accurate).
But what did it cost to squeeze a few more pounds of emissions out of the
air? Were there other ways to spend $44 million per year that might have

reaped greater gains? For those of us who waited in line for up to an hour to
have our emissions tested, what did that cost—time that could have been spent
making money, spending money, being with family and friends?
Not surprisingly, the real difference over the past 10 to 15 years is technol-
ogy has surpassed the ability of cars to pollute. Cars are running cleaner and
staying cleaner longer, and that has made the biggest difference.
It’s the car stupid!
Here’s my point. Data can provide an excellent rearview mirror into the past.
But it can be misused in the same way a drunk uses a lamppost: for support,
not illumination.
Forcing your data to support your point of view can lead to more defects, delay,
and cost. In the case of the 55 mph speed limit, there were more fatalities, more