Minor, perspective changing facts

Stuart_Armstrong

There's a lot of background mess in our mental pictures of the world. We try and be accurate on important issues, but a whole lot of the less important stuff we pick up from the media, the movies, and random impressions. And once these impressions are in our mental pictures, they just don't go away - until we find a fact that causes us to say "huh", and reassess.

Here are three facts that have caused that "huh" in me, recently, and completely rearranged minor parts of my mental map. I'm sharing them here, because that experience is a valuable one.

Think terrorist attack on Israel - did the phrase "suicide bombing" spring to mind? If so, you're so out of fashion: the last suicide bombing in Israel was in 2008 - a year where dedicated suicide bombers managed the feat of killing a grand total of 1 victim. Suicide bombings haven't happened in Israel for over half a decade.
Large scale plane crashes seem to happen all the time, all over the world. They must happen at least a few times a year, in every major country, right? Well, if I'm reading this page right, the last time there was an airline crash in the USA that killed more that 50 people was... in 2001 (2 months after 9/11). Nothing on that scale since then. And though there has been crashes on route to/from Spain and France since then, it seems that major air crashes in western countries is something that essentially never happens.
The major cost of a rocket isn't the fuel, as I'd always thought. It seems that the Falcon 9 rocket costs $54 million per launch, of which fuel is only $0.2 million (or, as I prefer to think of it - I could sell my house to get enough fuel to fly to space). In the difference between those two prices, lies the potential for private spaceflight to low-Earth orbit.

Here are three facts that have caused that "huh" in me, recently, and completely rearranged minor parts of my mental map. I'm sharing them here, because that experience is a valuable one.

Think terrorist attack on Israel - did the phrase "suicide bombing" spring to mind? If so, you're so out of fashion: the last suicide bombing in Israel was in 2008 - a year where dedicated suicide bombers managed the feat of killing a grand total of 1 victim. Suicide bombings haven't happened in Israel for over half a decade.
Large scale plane crashes seem to happen all the time, all over the world. They must happen at least a few times a year, in every major country, right? Well, if I'm reading this page right, the last time there was an airline crash in the USA that killed more that 50 people was... in 2001 (2 months after 9/11). Nothing on that scale since then. And though there has been crashes on route to/from Spain and France since then, it seems that major air crashes in western countries is something that essentially never happens.
The major cost of a rocket isn't the fuel, as I'd always thought. It seems that the Falcon 9 rocket costs $54 million per launch, of which fuel is only $0.2 million (or, as I prefer to think of it - I could sell my house to get enough fuel to fly to space). In the difference between those two prices, lies the potential for private spaceflight to low-Earth orbit.

At this point, you have to ask yourself whether you can even do any sort of reasonable meta analysis on the population. You're seeing clear differences between the populations and you can't just "compensate for them". If you take a sub-population which has numerous factors which increase their risk of some disease, and then "compensate" for those factors and still see an elevated level of the disease, it isn't actually suggestive of anything at all, because you have no way of knowing whether your "compensation" actually compensated for it or not. Statistics is not magic; it cannot magically remove bias from data.

Well, if you already know how much each of the associated factors contributes alone via other tests where you were able to isolate those variables, you can make an educated guess that their combined effect is no greater than the sum of their individual effects.

The presence of other studies that didn't show the same significant results weighs against it, but on the other hand such cases are certainly not unheard of with respect to associations that turn out to be real. The Cochrane Collaboration's logo comes from a forest plot of results for whether an injection of corticosteroids reduce the chance of early death in premature birth. Five out of seven studies failed to achieve statistical significance, but when their evidence was taken together, it achieved very high signficance, and further research since suggests a reduction of mortality rate between 30-50%.

While a study of the sort linked above certainly doesn't establish the truth of its findings with the confidence of its statistical significance, "never believe studies like this" doesn't leave you safe from a treatment-of-evidence standpoint, because even in the case of a real association, the data are frequently going to be messy enough that you'd be hard pressed to locate it statistically. You don't want to set your bar for evidence so high that, in the event that the association were real, you couldn't be persuaded to believe in it.

You can't make an educated guess that a combination of multiple factors is no greater than the sum of their individual effects, and indeed, when you're talking about disease states, this is the OPPOSITE of what you should assume. The harm done to your body taxes its ability to deal with harm; the more harm you apply to it, whatever the source, the worse things get. Your body only has so much ability to fight off bad things happening to it, so if you add two bad things on top of each other, you're actually likely to see harm which is worse than the sum of t... (read more)

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