How Reliable Are Online Reviews?

Josephine Wolff investigates:

While the cacophony of voices may be overwhelming, the percentage of customers who write reviews is actually quite low. In a 2014 study that analyzed data from a private apparel retailer’s website, [MIT professor Duncan] Simester found that only about 1.5 percent of customers, or 15 out of 1,000, write reviews. “And these customers aren’t representative, they tend to buy more niche items,” he says. Simester also discovered that about 1 in every 15 reviews of an item—about 5 percent—are written by people who haven’t purchased it. “And the problem is the other 985 customers rely on the reviews written by these 15 people.”

Some reviews, in fact, may be entirely false. Others may be planted by businesses to burnish their own reputations or tarnish those of competitors. … Bing Liu, a professor of computer science at the University of Illinois, who has studied review sites, estimates that roughly 30 percent of all reviews online may be fraudulent.