Survivor Bias and a Few Gentle Musings

O to survive in this world of broiling fortune. What tales the old scarred warrior can tell. Tales of battle and sweated bloodied brow, of deeds long fought, long ago. But what tales of the dead? They remain still and add nothing to the cacophony of war. If only they could speak. What tales would they relate? But dead men tell no tales.   Anon.

Today, I am in a wistful mood and feel moved to write about a couple of things that underly and guide our thinking processes.

During the Second World War, the American military was concerned about the survivability of their bombers conducting raids over Germany. Was there any way that the odds of survival could be raised to ensure that more planes, and men, came back after combat damage? Thus a survey was commissioned. Ground crews were tasked with recording battle damage on returning bombers and once this data had been collated from numerous planes it was respectfully passed on to the military hierarchy for rueful rumination. Below is a representation of that data.  The red dots record aggregated data points of damage.

The point of this exercise was to identify areas of the bomber that could be profitably reinforced with armour. Of course, it was impossible to reinforce the whole plane due to weight restrictions. However, it was possible to place limited armour in those areas likely to sustain combat damage. The Air force 'big hats' looked at the damage profile and pronounced: "We will reinforce those areas covered by red dots. No longer will our aircraft come back bespeckled/peppered with red dots!" The academic head of the study, Abraham Wald was mortified at their conclusion. How could they not see the real areas requiring armour protection? As a statistician, of renown, it was clear to Wald that extra protection was required in those areas not covered in red. Damage to these areas obviously caused catastrophic damage- these planes did not return home to add to the data collection. A classic case of 'dead men tell no tales'. Once pointed out this seems a clear conclusion to most folk. We are faced with similar situations, mayhap not so obvious as the above example, but they confront us on a regular basis, and just like the Airforce supremos we are oft to come to the wrong conclusion.

We are hard-wired to think the way of the 'Air force' as a legacy from our ancient past. Imagine you are on the savannah a million years ago and you are confronted by a large predator. What do you do: you have several options; run away; climb a tree; hit animal with a big stick, or ruminate carefully about the situation making sure you have assimilated all the relevant information before making a sound logical decision. It is my contention that our ancestors who picked the first three options were more likely to survive and thus produce progeny than the logical 'egg head'. We have been very much conditioned by this 'flight or fight' reflex, which served us well in evolutionary terms but has less relevance in modern (at least civilised society) where a measured, sound, and logical thinking process is paramount.   

Here is another example, although perhaps a little more subtle than the 'battle damage' scenario. It has been touted, by those who talk about this sort of thing, that a college education is not necessary for success. Just look at the founders of Apple and Microsoft, Steve Joby and Bill Gates (what happened to Paul Allen?). Both these individuals dropped out of college and went on to run multi-billion companies. Let us follow their lead and stride towards success and perhaps a hint of academic ignorance. Unfortunately, this limited data set is not in tune with wide reality. When we look at the stats we see that college graduates subsequently go on to earn more than their less well-educated brethren; achieve more life success in terms of material wealth and this even translates into a happier personal life. This must be true- statistics never lie. Perhaps we should look at the 'life-stories' of those folk who dropped out of higher education without achieving life-success- the so-called 'failures'. The salutary lessons learned from this cohort are more likely to have relevance to our ultimate reality than listening to Bill Gates, and supposed life coaches, droning on about the essential pathway to success. I suspect that Gate's perception of the 'right thing to do' would get a little hazy if we could whisk him back in a time machine to when those critical business decisions were made by himself and the other bloke. This hindsight thingy is wonderful, shame we can't have it when it is simply insight.

The point I'm trying to make in my peculiar and long-winded way is that there is often a good dose of 'luck' in life's proceeding- probably more than we would like to admit and more than we feel comfortable with. What would have happened to a young Kate Moss if she hadn't been discovered in an airport lounge? If she hadn't experienced a random, rare, and chance event would her innate drive and talent have conquered all anyway and propelled her to mega-success? Or would she have ended up as a checkout gel at the local 'MegaSuperSave Mart', everything under a quid, and owned by Mr. Patel-Mugumbo? I'll leave my gentle readers to judge.