The Differential Effects of Peer and Expert Ratings on Choice

Anne-Madeleine Kranzbühler, Mirella H.P. Kleijnen, Peeter W.J. Verlegh, and Marije Teerling, 2015, 15-117

Before purchasing complex services like financial or health care services, consumers often consult online platforms that provide ratings from peers and experts. While prior research has examined the effects of each type of advice on attitude formation and choice behavior, little is known about how the simultaneous presence of peer and expert ratings affects consumer decision making.

In three experimental studies, Anne-Madeleine Kranzbühler, Mirella Kleijnen, Peeter Verlegh, and Marije Teerling analyze the trade-offs consumers make when considering peer and expert ratings in a health care context. Their study provides insights into the interaction between these two distinct types of eWOM as well as an understanding of the underlying mechanisms that cause subjective ratings to overrule objective ratings and vice versa.

Based on data from an online panel (, their first study showed that when confronted with conflicting ratings on a health care rating platform, consumers generally favored peer over expert advice.

When questioned, consumers perceived peers (patients) to mainly judge a hospital on care-related factors that could easily be observed, while experts were perceived to focus on technical quality of procedures and equipment. Nevertheless, they tended to follow their peers’ rating when choosing a hospital.

In a second study, the authors found that rating volume was an important moderator of the impact of peer versus expert advice. Specifically, when confronted with conflicting information on hospitals, consumers tended to base their evaluations and usage intentions on expert rather than patient advice in case the patient advice was based on small numbers. However, when the group of patients substantially grew in size, consumers started to rely on the crowd rather than experts in making a decision. Interestingly, this suggests that consumers indeed trust the judgment of their peers, but only in large numbers.

A third study showed that the preference for peer advice can be mitigated when consumers first deliberate on both sources’ respective abilities and expertise.

Managerial implications

Peer and expert advice should be seen as complementary input to aid well-informed decision making. Companies can create awareness among their customers on how to beneficially use different sources of information.

Companies can influence the diagnosticity of peer and expert ratings by making consumers deliberate on both sources’ specificities. They can complement online ratings with ancillary information such as background information on sources’ abilities and expertise. This information needs not to be conspicuously present, but should be very accessible (e.g., by routing consumers through this information before being able to access the ratings).

By transparently illustrating all data sources used for the ratings as well as their respective origins, online rating platforms can increase overall perceived levels of trust and expertise.

Anne-Madeleine Kranzbühler is a Ph.D. candidate, VU University Amsterdam and VODW. Mirella H.P. Kleijnen is Associate Professor of Marketing and Peeter W.J. Verlegh is Professor of Marketing, both at VU University Amsterdam. Marije Teerling is Principal Consultant, VODW.

Related links

How Online Reviews Can Benefit Brands (2014) [Article]


  • Corporate: FREE
  • Academic: FREE
  • Subscribers: FREE
  • Public: $18.00



Employees of MSI Member Companies enjoy the benefits of complete online access to content, member conferences and networking with the MSI community.



Qualified academics benefit from a relationship with MSI through access to, conferences and research opportunities.



The public is invited to enjoy partial access to content, a free e-newsletter, selected reports and more.




Learn more about becoming a member of the institute

Read More

Stay Informed

The MSI Mailing List

Subscribe to our email list to stay informed about upcoming events, news, etc.

Social Media