29 April, 2012

Cause and effect: more likely than Welsh rugby killing popes?

According to modern Welsh legend:
Every time Wales wins the rugby grand slam, a pope dies, except for 1978 when Wales was really good, and two popes died.  
The grand slam refers to beating all other teams in the annual Six Nations rugby competition (between England, France, Ireland, Scotland, Wales and, in recent years, Italy).  In 2008, a paper published in the British Medical Journal asserted that there was no statistical evidence for this.  Last week, however, researchers debunked the earlier study for ignoring Coptic popes  Apparently, if both Catholic and Coptic popes are included, there is indeed a very high correlation between Welsh rugby success and papal demise.

Now, no-one really believes that any causal link actually exists; it is just a statistical coincidence.  But every day, we see impassioned advocacy for  all variety of causes using far flimsier evidence.  It's no better in business life or, indeed, family life.  We all do it - spot half-baked correlations, extrapolate them into cause and effect, and then make major decisions.

Next time someone presents some cause and effect claims as part of their business case,  ask yourself if the claim is any more likely than the one about Welsh rugby success killing popes.

No comments: