STEVE INSKEEP, HOST:
The other day on this program, we told you the story of a British novelist who apologized for abusing the Internet. RJ Ellory was caught writing bogus customer reviews on Amazon of his own novels, crediting himself with, quote, "magnificent genius," and also hammering his competitors. Ellory may not be alone, and that matters because so many of us depend on online customer reviews when we make consumer choices, not just about books but about movies, about travel companies, about hotels. NPR's Shankar Vedantam is here with some advice for us. He's going to help us try, at least, to sort to real reviews from the fake ones. Hi, Shankar.
SHANKAR VEDANTAM, BYLINE: Hi, Steve.
INSKEEP: So what makes this such a big problem?
VEDANTAM: Well, it becomes huge problem because online reviews feel powerful in a way that expert opinions often do not. So you think people like me went and ate at that restaurant. People like me went and stayed at that hotel, and you know, as you say, a few vivid examples of cheating have come to light from time to time, but most of the time you look at reviews and you can't tell the fake ones from the real ones.
I mean, if you're a customer and you're thinking of staying in a hotel and the review says the hotel has bedbugs, what would you do?
INSKEEP: I might stay there, actually, because I go to nightmare locations for a lot of my work. But in any case, yeah, many people would stay away from that. They would give that some weight.
VEDANTAM: Exactly. Now, it turns out the Federal Trade Commission actually prohibits you from writing fake reviews. There are actually penalties and fines attached to merchants who post fake reviews about themselves, or harsh reviews about their competitors, and many of these sites that host online reviews, Trip Advisor and Expedia and Yelp and so on, try and police fake reviews. So they try and use linguistic analysis, for example.
If the same language shows up in multiple reviews, it's a flag. It could also be that if one person has never posted a review before, and all of a sudden they post either a five-star review or a one-star review, that's also a flag that there might be fakery going on. I wanted to find out if there's a psychological profile of fake online reviews.
VEDANTAM: So I called this marketing professor at the University of Southern California, her name is Dina Mayzlin, and she told me to put myself in the mind of the person writing the fake review.
DINA MAYZLIN: What you're trying to do is to be indistinguishable from a real review. It's almost by definition very hard to tell the good fakes from the real reviews.
VEDANTAM: So it looks like there's really no simple psychological formula to look at a review and say this one's real, this one's fake.
INSKEEP: Although RJ Ellory apparently made the mistake of signing one of the reviews with his real first name rather than the pseudonym under which he was writing. So you can look for little clues like that.
VEDANTAM: Exactly. That clearly sounds like a work of magnificent genius.
INSKEEP: Okay. So we're stuck without an obvious answer. Is there a more subtle way to go about this?
VEDANTAM: So what Mayzlin has done is she's conducted this massive study comparing Trip Advisor and Expedia.
VEDANTAM: So on Trip Advisor all you need is an email address and you can say I stayed at this hotel, here's my review. On Expedia, you actually have to have bought the hotel room through Expedia...
INSKEEP: Because they sell hotel rooms among things, right.
VEDANTAM: Exactly. And so the reviews on Expedia are much more likely to be from verified customers than the review on Trip Advisor. And when Mayzlin looked at hundreds of thousands of reviews of 3,000 hotels on these two sites, she found Expedia reviews tended to be more, you know, in the middle, more moderate, and the Trip Advisor reviews tended to be more on the extremes, either very positive or very negative, and Mayzlin thinks those are probably the fake reviews.
INSKEEP: We've got a producer listening in who adds one more wrinkle to this, though. We want to steer away from the extremist reviews because they might be fakes, but on the other hand, people tend to write in about something when they have really strong feelings about it, like they had a really horrible hotel experience. Couldn't some of the more extreme review be totally true?
VEDANTAM: They could be totally true, and I think this is the issue, which is you can't look at a five-star review or a one-star review and by itself say that this review is fake or real, but what you do is by comparing these two different sites, Expedia and Trip Advisor, you say the five-star reviews on Trip Advisor are more likely to be fake than the five-star reviews on Expedia.
One of the other things that Mayzlin pointed out is that the value of online reviews might not be whether a customer gives it one star or five stars, but in the specific details they give you. So you know, an online review might tell you the hotel swimming pool stays open till 9:00 in the evening, and that's valuable information. Or the hotel may say we're two blocks from the beach, but the online review can say those are two really giant blocks from the beach.
And she told me that she was booking a Caribbean vacation recently, and the travel agent was pressuring her to make a decision, but she felt that she hadn't done her due diligence, so she went online and looked at the properties that she was considering.
MAYZLIN: Right before I booked it, I looked at online reviews. These people were saying there were these pools where clothing was optional, and it turned out they were nudist clubs, and so, you know, I just was not happy to do that.
INSKEEP: Wasn't her style.
VEDANTAM: Wasn't her style, Steve.
INSKEEP: NPR science correspondent Shankar Vedantam. He tells me that reviews for his reporting are in and they're glowing. Congratulations, Shankar, I'm very proud of you.
VEDANTAM: Thank you, Steve.
INSKEEP: Tell him what you really think about his work on Twitter @hiddenbrain, and while you're at it, you can follow this program @morningedition and @nprinskeep.