5 Whys and the Monumental Mystery

There is a compelling story, so beloved of professional problem solvers that it has become a virtual “article of faith” in the 5-Whys community. So compelling, that although the work predates Google by almost a decade, and despite never warranting an official publication, there are nevertheless more than 140,000 pages online which reference the study in some way.

To recap, 5-Whys is a simple, stripped-down method of root cause analysis (RCA) in which the investigator repeatedly asks, “why?” in order to drill down from higher-level symptoms to the underlying root cause(s) of a problem.

The story covers the woes of the Jefferson Memorial in Washington DC and dates back to the late 1980s when the National Parks managers noticed that the memorial was crumbling at such an alarming rate that it would quickly become dangerous to visitors. When they asked why this could be, they discovered that it was being washed far more frequently than any of the other DC memorials. For most investigations, the analysis would go no further. The solution is clear, of course. Reduce the cleaning schedule to match those of the other memorials.

Unfortunately, that solution would have only led to a very dirty, unhygienic Jefferson Memorial. This clearly wouldn’t do in a city of such national and international significance.  By employing classic 5-Whys thinking there was clearly more work to be done!

Next up the investigation team enquired as to why the memorial was being cleaned so frequently?  They discovered it had an exceptionally large amount of bird droppings deposited on it every day. What’s the solution now? Use scarecrows? Fly hawks? Bring in Elmer Fudd or the Duck Dynasty crew and declare open season on pigeons?

Luckily (for the pigeons, anyway), the Parks managers kept inquiring. When they asked why the birds seemed to soil Jefferson at rates higher than other nearby monuments like Kennedy or Lincoln, they discovered that the Jefferson harboured an incredibly large population of spiders and similar bugs upon which the birds were eagerly feasting. Why on earth was this?  An eminent entomologist, Prof. Don Messersmith was contacted, and he discovered that the population of spiders had exploded because of an abundance of midges and similar insects that had made the area around the monument their home.

When the Parks managers asked Prof. Messersmith why so many midges congregated on the Jefferson memorial, Messersmith told them what any fly- fisherman already knows - Midges are triggered to emerge and mate by a particular quality of gentle light.  And it just so happens that the Park managers had been inadvertently creating this unique quality of brightness by turning the memorial lights on just before dusk.
So, according to our tale, this one variable (light levels) caused this pattern of cause and effect; lots of midges, lots of spiders, lots of pigeons, lots of droppings, lots of chemicals during lots of washing – all leading to the deterioration of the statue. 

Expressed as classic 5-Whys we can illustrate this in the following way:

Problem: One of the monuments in Washington D.C. is deteriorating.

Why #1 – Why is the monument deteriorating?  

• Because powerful chemicals are frequently used to clean the monument.

• To clean off the excessive volume of bird droppings on the monument.

• Because the large population of spiders in and around the monument are a food source to the local birds.

• Because vast swarms of flying insects, on which the spiders feed, are drawn to the monument at dusk.

• Because the lighting of the monument in the evening attracts the local insects.