Internet Activity Bias Causes Lumpy User Behavior

Jakob Nielsen’s Alertbox  • September 1, 2013

During preparations for our new training course on Analytics and User Experience, I discovered recent research that invalidates many simplistic approaches to website metrics. I’m ashamed to admit that it took me two years to appreciate these results, but the papers were written by economists that I normally don’t follow. Even though this research was done by economists and not usability people, it’s the most important new insight into web user behavior since information foraging and information scent. The basic finding is that users’ behavior is much lumpier than previously recognized: for any given user,periods of unusually high Internet activity alternate with periods of low activity.So, once again, this means that you can’t conclude that exposure to a specific stimulus causes a certain behavior, even if you observe increased occurrences of this behavior after the exposure. As I’ve always said,correlation doesn’t prove causation because hidden covariants might exist. We now know that user activity bias is one such covariant — and that it’s very strong.

Do Promo Videos Make People Visit Websites?

At Yahoo, Randall A. Lewis and his colleagues ran an experiment in which they asked visitors to Amazon’s Mechanical Turk service to watch a promotional video for Yahoo. The following chart shows whether these users visited any of the sites within the Yahoo network on the day they watched the video, as well as during the two weeks before and after their video exposure.

Users visiting a site before and after watching a promotional video for that site as well as a control group taht watched an unrelated video. Chart replotted after data published in Lewis et al. (2011).



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