June 14, 2014

Why is this week unlike every other week?

Keith Humphreys, writing in New York Magazine

clever new study in the journal Addiction provides clues about who is worst at owning up to the full extent of their drinking.

The researchers surveyed over 40,000 people with standard alcohol survey questions about their quantity and frequency of alcohol consumption — “How many drinks have you had in the past month?” and so on. But in a smart twist, they then asked a more immediate question: “How many drinks did you have yesterday?”

I’ve written about this technique before; it can be very powerful, though it won’t help much if people are intentionally misleading you.

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »

Comments

  • avatar

    Was their survey of conducted on multiple days of the week? Because drinking is not randomly distributed Monday-Sunday.

    4 months ago Reply

    • avatar
      Thomas Lumley

      Yes, the survey was conducted on every day of the week and reweighted to give equal representation of days. It also had equal representation of months over the year.

      There’s a smaller potential bias from people who couldn’t be contacted at the first attempt — it’s possible that being contactable is correlated with having drunk the previous day even conditioning on day of the week. But that’s a much less serious bias.

      4 months ago Reply

  • avatar
    Megan Pledger

    I can’t believe that anyone thinks that the question “How many drinks have you had in the last month?” is going to get an accurate answer from any drinker.

    4 months ago Reply

    • avatar
      Thomas Lumley

      That isn’t the question they asked. They asked about frequency of drinking and typical amount.

      4 months ago Reply

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