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Have you ever heard then statistic...

"You're never further than 20ft away from a RAT!"

...well it's not true.

So, why is it quoted like that?! Clearly someone quite clever has worked out the maths and come up with that statistic and now it's being quoted as a fact. But, they've made a fundamental mistake, and I'll explain what I think has happened. Here's how it works:

Supposing in a Westernised civilised society there is a rat-population which is estimated at however many million rats there would typically be. No, they don't go and count them all! It's an estimate, and if it's done scientifically it'll be within about 30%. Also, the land area of the country is known to be a certain number of square miles. That can be quite accurately measured using map-making technology. Now, if the total area of land is divided by the number of rats, a figure is come to which represents the average amount of land area per rat. The typical sort of result is in effect a piece of land 28ft square. So, if you imagine that, this hypothetical piece of rat-land with a rat in the middle, then keeping it simple, the furthest you could be away from the rat would be about 20ft. Further away and you'd be getting closer to the next rat along.

Crazy as it seems, the land area of a country divided by the rat population really does come out to this type of figure.

But this does NOT mean that you are always within 20ft of a rat! The reason is quite simple: Rats are not equally spaced!

If the rats were equally placed on a grid-pattern on a conveniently flat land, then you'd see it would be difficult to be further than the allotted distance from any of the rats. But rats, notoriously clever critters that they are, aren't going to hang around on a grid pattern for anyone to get a tape-measure to them, and they'll be off to the rubbish dump and down rat-holes before you can say "squeak". Rats will congregate in places where there's the best left-over food, the most comfy rat nesting places, and the environments that are safest from species considered to be non rat-friendly, and generally that means NOT within 20ft of YOU or any other humans!

What's interesting about the phenomenon of the "near to a rat" statistic is that THEORY has been applied in preference to common sense! Whilst the calculations are correct about the areas and populations, and the sums are right, the assumption of equal spacing of rats gives a nonsensical inference, and then a belief has been propagated, based on FAITH in Experts.

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Other misconceptions are explored at the page: Misconceptions