Off by 100% Bias



When you tell a customer something is 125% better, they’ll think it’s only 25% better.

This is the Off by 100% Bias.

That new Black & Decker vacuum cleaner that claims to last 125% longer? Its performance will seem underwhelming.

Telling people their energy usage is 108% more than other households? They’lll underestimate how much of a power hog they are.

Of course, increasing their prices by 110% is likely to be underestimated, too. That is, until they get your bill!

If you want your number to have an impact, the lesson is to describe the improvement as a frequency rather than a percentage

For instance, saying something "lasts 2 times as long" or has "double the power" is likely to be more impactful than saying it lasts "100% longer" or is "100% more powerful."


P.S. Did you notice in the video I incorrectly used 200% for double the performance? 😱


See Just Do This for more. 

Ref: Matthew Fisher, Milica Mormann, The Off by 100% Bias: The Effects of Percentage Changes Greater than 100% on Magnitude Judgments and Consumer Choice, Journal of Consumer Research, Volume 49, Issue 4, December 2022


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