Smoking, Social Desirability Bias, and Dark Matter

At the IEA blog, Kristian Niemietz points out that expenditure surveys fail to detect most of the tobacco sales visible in national product accounts. 

For most goods, the two show broadly the same pattern: with small errors, what people profess to buy grosses up to what is really being sold in the country. But tobacco is a big exception. Less then half of the recorded cigarette purchases shows up in the Living Cost and Food Survey. In the US equivalent, the ratio is not even 40%.

Why is tobacco dark matter?  Social Desirability Bias!

The mismatch between what smokers say in surveys and what they do in
practice is a classic example of the difference between “stated preferences” and “revealed preferences“. Social engineers love stated preferences. Opponents of big supermarkets, too, always have a survey at hand, indicating that the vast majority of residents in their areas would never set foot in a discounter. But once it is there, it flourishes.

There is nothing schizophrenic about this behaviour. When asked whether you would shop in a big supermarket in your area, of course you respond something like “No! Small, local shops are much more charming and personal” – because that is the socially acceptable thing to say. When you smoke, saying that you want to quit makes you at least a repentant sinner.

Now ask yourself: Is voting more like a national product account – or a consumer expenditure survey?

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