Juks med online vurderingar #2

Juks med online vurderingar er eit problem for dei som driv nettsider som Tripadvisor.com og Hotels.com og til sjuande og sist for dei som eig eller driv bedriftene som blir påverka av slik juks.

Eg har tidlegare skrive om korleis ein artikkel av Luca og medforfattarar har funne at restaurantar juksar når dei har få vurderingar eller nyleg har fått ei dårleg vurdering, at restaurantar som høyrer til ei kjede juksar mindre, og at tøffare konkurranse aukar sjansen for juks med negative vurderingar.

Svakheita med den artikkelen var at forfattarane brukte Yelp.com sin eigen algoritme for å identifisere juks, og at det er uklart kor god denne er. Ein ny artikkel som snart blir publisert i American Economic Review brukar ein betre metode for å identifisere juks. Forfattarane (Mayzlin, Dover og Chevalier) brukar forskjellen på vurderingane på Expedia.com (der kun dei som faktisk har bodd på eit hotell kan skrive ei vurdering) og Tripadvisor.com (der alle kan skrive ei vurdering) til å avdekke juks. Funna liknar mykje på Luca et al. sine, kjedehotell oppfører seg betre, og konkurranse gir meir juks.

Heile samandraget:

Online reviews could, in principle, greatly improve consumers» ability to evaluate products. However, the authenticity of online user reviews remains a concern; firms have an incentive to manufacture positive reviews for their own products and negative reviews for their rivals. In this paper, we marry the diverse literature on economic subterfuge with the literature on organizational form. We undertake an empirical analysis of promotional reviews, examining both the extent to which fakery occurs and the market conditions that encourage or discourage promotional reviewing activity. Specifically, we examine hotel reviews, exploiting the organizational differences between two travel websites: Expedia.com and TripAdvisor.com. While anyone can post a review on TripAdvisor, a consumer can only post a review of a hotel on Expedia if she actually booked at least one night at the hotel through the website. We examine differences in the distribution of reviews for a given hotel between TripAdvisor and Expedia. We exploit the characteristics of a hotel’s neighbor. We show that hotels with a nearby neighbor have more one- and two-star (negative) reviews on TripAdvisor relative to Expedia. We argue that the net gains from promotional reviewing are likely to be highest for independent hotels that are owned by single-unit owners and lowest for branded chain hotels that are owned by multi-unit owners. Our methodology thus isolates hotels with a disproportionate incentive to engage in promotional reviewing activity. We show that the hotel neighbors of hotels with a high incentive to fake have more one- and two-star (negative) reviews on TripAdvisor relative to Expedia than do hotels whose neighbors have a low incentive to fake. Furthermore, we show that hotels with a high incentive to fake have a greater share of five-star (positive) reviews on TripAdvisor relative to Expedia.

Referanse:

Mayzlin, Dina, Yaniv Dover, and Judith A. Chevalier. “Promotional Reviews: An Empirical Investigation of Online Review Manipulation.” American Economic Review (Forthcoming). http://www.nber.org/papers/w18340.

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