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The widely quoted “270%” review stat comes from one gift retailer

September 2026 · Luca

Two questions tend to get merged into one. Do online ratings change which provider people choose? And does showing reviews on your own website bring in more bookings? The first has good evidence behind it. For the second, I could not find a study that measured it.

The cleanest evidence comes from restaurants

Proving that a rating causes more customers is hard, because good businesses get both good ratings and more customers. Two economists, Michael Anderson and Jeremy Magruder, found a way around that, published in The Economic Journal in 2012.1

Yelp rounds a restaurant’s average to the nearest half star. A restaurant averaging 3.74 is shown with 3.5 stars, and one averaging 3.76 is shown with 4, although the two are practically identical. Comparing restaurants just either side of that line isolates the effect of the star that people see.

The researchers matched 328 San Francisco restaurants with an online reservation site and, from July to October 2010, recorded whether a table for four was still available on Thursday, Friday and Saturday evenings.

• +19percentage points: how much more often 7 pm tables sold out with an extra half star
• 49%the same effect in relative terms, as the authors report it
• 20 to 30percentage points among less well known restaurants (100 to 500 reviews)

This is the result closest to a small business. For restaurants with more than 500 reviews, the authors found no jump at all. In the authors’ words, the impact is larger “when alternate information is more scarce”.

What patients say

For healthcare there is no equivalent experiment that I found. There are surveys, and a survey measures what people say, not what they do.

A national US survey, published in JAMA

In September 2012, researchers at the University of Michigan surveyed a sample weighted to represent the US population. 2,137 people answered, a 60% response rate.2

• 59% called physician rating sites somewhat or very important when choosing a doctor. They still ranked them below insurance, location, experience and word of mouth.
• 65% knew such sites existed.
• Among those who had looked up physician ratings in the past year, 35% said they had chosen a doctor because of good ratings and 37% had avoided one because of bad ratings.

111 plastic surgery patients, published in 2026

A survey by the University of Tennessee Health Science Center asked 111 adult plastic surgery patients how they used online reviews.3

• 45% had researched their surgeon before the visit.
• 8.3% had found their surgeon through online reviews.
• 77% considered online reviews both accurate and important.

The opinion (77%) is high, while the reported behavior (8.3% found their surgeon that way) is much lower. Reviews seem to work more as a check on a clinic people already heard of than as the way they find one. That is my reading of these two figures, and the sample is small.

Where the 270% figure comes from

A figure you will find repeated widely comes from a 2017 report by the Spiegel Research Center at Northwestern University: the purchase likelihood for a product with five reviews was 270% greater than for a product with none.4

Before repeating it, consider how it was produced:

• It was produced in partnership with PowerReviews, a company that, in the report’s own words, works with brands and retailers “to collect and display customer ratings”.
• The 270% comes from one online retailer of high end gifts: about 15.5 million page views of 1,800 products over one year.
• It is observational. It compares products as they gathered reviews, not a controlled test. The report says five reviews “causes” the increase. My objection, not the authors’: products that already sell well collect reviews faster, so part of the difference may run the other way.

The report describes that retailer well. It tells us nothing direct about a clinic, and it does not prove cause.

How a number grows as it travels

A 2020 study in the Annals of Plastic Surgery looked at a single clinic: the chief resident clinic of an urban plastic surgery training program. The authors are at the Icahn School of Medicine at Mount Sinai, New York.5 After one positive review was posted on RealSelf, aesthetic cases went from 82 to 107 in the following academic year, a 30% growth rate against about 10% a year before. There was no comparison group, and the authors attribute a large part of the increase to one procedure, facelifts.

Six years later, the introduction of the 2026 survey above summarizes it this way: a single positive review “was associated with a 30% increase in aesthetic surgery volume.”3

Nothing in that sentence is false. But the one clinic, the missing comparison group and the facelifts are gone, and what is left reads like a general rule. It happened in a peer reviewed medical journal. That is the reason every figure on this page links to where it was measured.

What I take from this for a clinic

• People do look at ratings before choosing a doctor or surgeon, by their own account.
• Where the effect of a visible rating could be isolated, it was large, and largest for the less known businesses.
• I found no study measuring what happens when a clinic shows its reviews on its own website. So I don’t promise a number.
• What I do check in an audit is simpler: whether a visitor can see any reviews, ratings or testimonials on the site at all, and whether the site points to the clinic’s reviews on Google or Yelp. I can see those on the page. What they do to revenue I cannot measure.

Sources

Each source was opened and read before this page was written. Where a study is a survey, or was produced with a company that sells a related product, it says so.

1. Anderson, M., & Magruder, J. (2012). Learning from the crowd: Regression discontinuity estimates of the effects of an online review database. The Economic Journal, 122(563), 957 to 989. doi.org/10.1111/j.1468-0297.2012.02512.x Design: regression discontinuity, a quasi experimental method, peer reviewed. 328 San Francisco restaurants, reservation availability recorded July to October 2010.
2. Hanauer, D. A., Zheng, K., Singer, D. C., Gebremariam, A., & Davis, M. M. (2014). Public awareness, perception, and use of online physician rating sites. JAMA, 311(7), 734. doi.org/10.1001/jama.2013.283194 Design: survey, nationally representative internet panel (GfK KnowledgePanel), September 2012. 2,137 respondents, 60% response rate.
3. Wei, E. Z., Asserson, D. B., & Becker, D. B. (2026). The utilization and influence of online review websites in plastic surgery. Plastic Surgery, online ahead of print. doi.org/10.1177/22925503261419806 Design: cross sectional survey. 111 adult plastic surgery patients.
4. Spiegel Research Center, Northwestern University, with PowerReviews (2017). How online reviews influence sales. spiegel.medill.northwestern.edu/how-online-reviews-influence-sales Type: industry report, not peer reviewed, co-produced with PowerReviews, a company whose business is collecting and displaying customer reviews. Observational data from online retailers.
5. Sanati-Mehrizy, P., Margulies, I. G., Sayegh, F., Ingargiola, M. J., & Taub, P. J. (2020). The “RealSelf Effect”: Can patient reviews on social media impact clinic volume? Annals of Plastic Surgery, 85(4), 352 to 357. doi.org/10.1097/SAP.0000000000002245 Design: retrospective before and after comparison at one clinic, no control group. 1,734 cases from 2012 to 2018.