Whoever first reviews my book on Amazon* had better give it five stars, because it turns out that recommenders can skew results:

Researchers from the University of Minnesota have shown that the way recommender systems are set up can affect the opinions they evoke, and that artificially high or low recommendations can raise or lower subsequent recommendations.

The researchers study showed that lying by skewing rankings higher or lower biases subsequent ratings in that direction, and that the distortion this chain of events induces may influence consumer buying in the short-term, but adversely affects long-term consumer trust in the system.

The bottom line is that displaying a prediction introduces bias. The researchers’ work is also consistent with a long line of psychology studies showing that people shift opinions to conform to a group.

* AND NO, THIS IS NOT MORE ABJECT BEGGING!