Archive for March, 2007

Paul Kedrosky has a post concerning a recent study that indicated that fireman are more likely to die from a heart attack than from fighting a fire while on duty.

Firefighting is known to be a dangerous occupation. What is less appreciated is that the most frequent cause of death among firefighters is heart disease rather than burns or smoke inhalation. Cardiovascular events, largely due to coronary heart disease, account for 45% of deaths among firefighters on duty.

Paul writes that people find this fact surprising (or maybe ironic) as an example of the Conjunction Fallacy:

Given that they fight fires, and that is a well-known hazardous occupation, you might think that the mortality risk from fire-fighting would dominate the risk from other causes of death. The trouble is, literally, that coronary disease is so widespread in the population that the incremental increased risk from it is not sufficient to make it more likely that firefighters die fighting fires than from heart attacks.

There are also elements of the Availability Heuristic at work here – people tend to overestimate the probability of sensationalistic events over common events:

When asked to rate the probability of a variety of causes of death people tend to rate more “newsworthy” events as more likely. People often rate the chance of death by plane crash higher after plane crashes, and death by natural disaster as too likely only because these events are more reported than more common causes of death. Other rare forms of death are also seen as more common than they really are because of their inherent drama: shark attacks, terrorism, etc.

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One might think that successful people are the ideal for asking advice about how to be successful (and there is a large industry of how-to books along these lines). For a variety of reasons, this is probably not the case.

People have a strong tendency to attribute to skill everything they did right and luck to everything they did wrong. In reality, it’s best to think of the world as a very large roulette table (or Russian Roulette depending on your predicament) – skill will allow you to place more bets on the table but it’s not a guarantee of success. Couple this bias with the lack of data and an inability to reproduce the experiment – people generally don’t have the ability to rerun their lives to determine what would have happened if they had made some choice differently. This is where Survivor Bias appears – by asking the successful, your ignoring all the people who were unsuccessful.

Another problem with this type of advice is the Single Cause Fallacy – people tend to look for a singular causal factor for an event. A good example of this is the popular business news “explanations” for why the Stock Market moved by < 1%  – the reality is this is just random fluctuations but this doesn’t make for a great story so they feel compelled to invent a reason. The Texas Sharpshooter Fallacy is also quite prevalent – a gunslinger fires bullets at a wall and then draws a target around the bullet holes concluding that he is an expert marksmen. Asking for advice requires the person to come up with a reason after the fact that fits the data when there may not be an explanation at all.

Even if someone was successful for a specific reason and was aware of the causal relationship, specific advice is usually only useful in a specific context – what worked for them will likely not work for you.

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