Radical Market Research Idea #5: Drop the decimals #MRX


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Pull out the last research report you wrote. Flip through until you get to a paragraph full of percentages. You know, 43.76% of consumers like this, 28.382% of consumers prefer that.  Look at and admire the decimal places. Aren’t they lovely.

But tell me, if all of the following examples are based on a survey of 1000 people, in which case would you make the business decision to produce the blue product?

  1. 40.001% of people prefer the pink version whereas 40.002% of people prefer the blue version
  2. 40.01% of people prefer the pink version whereas 40.02% of people prefer the blue version
  3. 40.1% of people prefer the pink version whereas 40.02% of people prefer the blue version

I certainly hope that none of those situations would lead you to conclude that the blue version is preferred over the pink version. Now try a few more options.

  1. 40% of people prefer the pink version whereas 41% of people prefer the blue version
  2. 40% of people prefer the pink version whereas 43% of people prefer the blue version
  3. 40% of people prefer the pink version whereas 45% of people prefer the blue version

So here’s my request. Enough already with the decimal places. They give us a false sense of precision and they are useless at clarifying major business decisions. If two percentages are so similar that decimal places are required, you’ve got nothing. Move on. Try again. Stop wasting your time. Radical?

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7 responses

  1. […] Radical Market Research Idea #5: Drop the Decimals – Annie Pettit argues we should stop offering the illusion of precision and drop decimal points […]

  2. We were discussing this in the office just yesterday. Accuracy and specificity. Too often confused.

  3. At some point, these decimals are vital in making crucial decisions.

    1. They CAN be crucial but too often we put them in not because they are required, but because we are just used to putting them in. And that is the wrong reason.

  4. About the decimal thing – research report writers really use 3 decimals in their reports? Does anyone hire them again?
    As for Jeffrey’s radical idea, disclosing intelligibly the sampling margin of error is a fun idea … of course that’s not addressing other errors.
    How about simply focus on business decisions and how best to support them. As someone once wrote: what business decisions are made only at a 95% confidence interval? Practically, they suggested, all kinds of important business decisions get made when odds are 2:3 in favour …

    1. Totally agree. The only thing that matters is the business decision. I would love to hear from someone who actually made a business decision based on the third decimal point.

  5. One of my first managers called the decimal point the medium of “spurious precision” and said it offered the illusion of authority. It will be hard for me to give it up. Do you have a 12-step program?

    Should you go even further and say “38-42% of people prefer the pink version whereas 41-47% of people prefer the blue version”? Not that’s radical!

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