# Choose an appropriate level of accuracy

Mar 10, 2015

“The more cheese, the more holes; but the more holes, the less cheese. Therefore the more cheese, the less cheese.” So goes the paradoxe du fromage à trous. Nothing that couldn’t be fixed with a little more accuracy on what we mean.

So, accuracy—the conformity to truth or to a standard or model (per Merriam-Webster)—is desirable. But past a certain amount, striving for more accuracy isn’t necessarily beneficial.

## Don’t let looking for more accuracy prevent you from getting a sense of what’s going on

I lived in the US on and off for about 13 years. There, they measure temperatures in Fahrenheit degrees. However I was raised in Europe where Celsius is the norm and my brain still prefers them. No problem, converting Fahrenheit to Celsius is simple: Subtract 32 and multiply by 5/9. But doing the calculation mentally on the go can be a little off putting, and it’s easy to give up.

There is an easier alternative, if you’re ready to give up a little bit of accuracy: Subtract 30 and halve. The figure below shows that the approximation isn’t bad—at least if you’re interested in deciding whether you should wear a sweater or not—and the operation can be carried out mentally with less effort than the exact one.

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Taking a temperature in Fahrenheit, subtracting 30 and halving it yields an approximate in Celsius that is good enough for many practical applications.

In this situation, if going for the exact number means that you might give up along the way, perhaps you should just settle for the approximation. That is, you shouldn’t let your quest for a more accurate result get in the way of getting a sense of what is going on, especially when the added accuracy is not critical and the added effort is nontrivial.

Here is another example. Early maps of the London underground were superimposed on road maps. Although they accurately reflected distances, this accuracy implied that the stations in the center of the city closely clustered—as they are in reality—which made it hard to read the map.

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Following Beck’s approach, many modern underground maps let go of “traditional” accuracy to favor clarity (http://tfl.gov.uk/maps/track).