Math makes my brain hurt, I admit. But, like most of us, I do basically understand odds, or at least the concept behind them.
So when I read something that makes me go “Whaa?” I do a little research, so I don’t ask and look like an idiot. Only this time, my research made me to “WTF?” and now, at the risk of looking like said idiot, I’d like someone to explain this to me.
The estimated population of Planet Earth right now is, roughly, 6.6 Billion humans.
The definition of the word Quadrillion is “one billion million” (roughly Bill Gates net worth).
So, if a forensics lab is quoted in a newspaper article as saying “The odds of taking some random stranger’s DNA and having it match perfectly are 1 in 19 Quadrillion.” that makes me wonder . . . This guy/gal is saying that the odds of finding another human with matching DNA are, technically, 1 in 19 million billion – only the population is 6.6 billion.
Isn’t this a bit over exaggerated? Can’t he simply say “The DNA was a one hundred percent match.” Why does he just suggest that, should the population increase by – well my brain hurts – but the population of Earth would have to increase exponentially until we simply didn’t fit here anymore, and THEN the odds might be 1 in 19.
For the love of crab apples – it sounds like one of those over-the-top writers who elaborates page after page about how the heaving-breasted woman’s perfume smelled, when a simple “she wore perfume” would suffice.
And by the way, there is no scientific evidence that no two fingerprints are alike – until the entire 6.6 billion people here have been fingerprinted, no one can make that claim. Add to that the very poor ratings used in the US – an 8-point match – when other countries demand a bare minimum of a 20-point match before even coming close to IDing a fingerprint match – is appallingly Hollywood.
/strangely unrelated rant.
2 thoughts on “can someone ‘splain this to me?”
I think that the odds are based on the number of permutations of the DNA components. Not on the number of current expressions (people) of those components.
Also, thanks for the stories that used to be on your web site and your recent Friday series. More pretty please.
Because they’re scientists. They don’t believe anything with absolute certainty.