What Really Caused the Epidemic

Ever since the dawn of the Enlightenment in the 17^th Century, Cause and Effect has been a key method used by scholars and scientists to solve complex problems and make informed decisions.  One of the most difficult aspects of understanding Cause and Effect is to be able to master which information you need to include and what you can ignore.  As essayist, and former risk analyst Nassim Taleb stated ‘It’s easy to think intelligence is about noticing when things are relevant (detecting patterns). In a complex world, intelligence consists in ignoring things that are irrelevant (avoiding false patterns)’.

In Cause and Effect logic we rarely uncover single causes to any event (if only life were so simple) and therefore we embark on analysis of what we call ‘causal sets’, thereby working out exactly what combination of causes were ‘Necessary and Sufficient’ to create a given effect.  A kind of Cause and Effect version of Ockham’s Razor. In practice, we look at an effect and ask ourselves ‘if one of the causes is removed, will the effect still occur?’, followed by asking ‘are the remaining causes sufficient in themselves to explain the event in full?’ 

Put another way, if our selected causes are all necessary for the event to happen then altering any of these MUST change the outcome in at least some way. Also, as a group, they must be sufficient to explain the event happening as it did, with ZERO additional causes needed to explain the event.



In Malcolm Gladwell’s seminal bestseller from the year 2000 ‘The Tipping Point’ we can see an explanation of ‘Necessary and Sufficient’ in action.  He begins his discussion by looking at the episode of a major syphilis epidemic that rocked the US city of Baltimore at the end of the 20^th century.

What could have caused this dramatic and devastating increase?  Gladwell’s research unearthed four causes that can be considered both necessary and sufficient. 

Firstly, the disease had been prevalent in the city for generations.  Though it should be noted that for decades the infection rate had remained constant before suddenly sky-rocketing in the summer of 1996. 

Secondly the CDC reported that in 95/96 Baltimore experienced a notable increase in crack cocaine usage, which led to a substantial increase in what authorities would later describe as “risky behaviour”, allowing diseases like syphilis and HIV to spread with greater ease.

Academics at John Hopkins University then revealed another factor; that there had been federal cuts in medical services, particularly in poorer areas, reducing disease control services by up to a third. Meaning that, on average, an infected person was carrying the disease for three to four times longer before receiving treatment.

Finally, one of the US’s leading epidemiologists pointed to a fourth necessary cause.  In the mid-1990s Baltimore famously set about destroying two large 1960’s public housing projects in the city, one in the east and one in the west.  This led to the migration of two previously isolated communities, communities that up until this point had been relatively self-contained socio-sexual environments.

What this suggests to us from an RCA perspective is that this seemingly straight-forward occurrence can only be fully explained by these four causes working in combination – causes that are all necessary and sufficient to this epidemic. The first involved the disease itself, the next changed behaviour, the third triggered a change in safeguard procedures and the final one radically changed the environment.  While none of the causes were that dramatic in isolation (note that the medical services were reduced by a third, not abolished) in combination they allowed a dynamic and damaging change to occur. Remove one of these causes and you will still have a large increase in the number of infected people, but not a major epidemic.  And no other causes need to be added to this ‘causal set’ to account for the major epidemic either.

In Root Cause Analysis we gather and manage data in a structured way, allowing us to open our thinking as to how seemingly small and unconnected causes coexist to create events that are, on occasion, enormous. Thereby we position ourselves to be able to understand causality in full and apply multiple solutions that will prevent or reduce the problems we encounter.

If you want to know more about how our Root Cause Analysis and Tactical Problem Solving methodology could help your organisation solve problems, reduce risk and improve performance please contact us.