Quantity matters, at least when it comes to product reviews. New research finds that consumers are swayed by the number of reviews an item receives, even if it's of worse quality. Quartz reports that the study analyzing buying habits on Amazon shows that online products with the most reviews were the most popular, even if they scored a lower rating. "We found that people were biased toward choosing to purchase more popular products and that this sometimes led them to make very poor decisions," says Stanford's Derek Powell, per a press release. After studying 15.6 million reviews of more than 350,000 Amazon products, Powell and his team built a statistical model mimicking how people shop.
Writing in Psychological Science, Powell's team then asked participants to choose between two products that scored the same rating of 3.1 stars, but with different review tallies—29 for one and 154 for the other. In 90% of the cases, participants said they'd buy the item with more reviews. The scientists found no relationship between the number of reviews and a product's average rating; there was only a 40% chance the more popular product was rated better quality. So how do you prevent humans from using online information to make, as Powell puts it, "systematically bad decisions?" Lifehacker suggests that people actually read the content of online reviews before buying. Powell agrees that more buyer-side caution is called for, but he tips the ball back to retailers, suggesting they "might need to rethink how reviews are presented." (One confused shopper pans a weed grinder.)