June 12th, 2012 | 3 MIN READ

Best Practice Mythbusters #1: When Social Proof Doesn’t Work

Written by author_profile_images Linda Bustos

Linda is an ecommerce industry analyst and consultant specializing in conversion optimization and digital transformation.

One man's best practice is another man's conversion killer. The first instalment of "Best Practice Mythbusters" looks at social proof. In theory, showing off how popular you are should grok AIDA - grab Attention, spark Interest, create Desire and push visitors toward Action. But there are cases where social proof lowers conversion. But is there more to it?

WhichTestWon.com recently featured a case from Moneysupermarket.com which tested customer ratings vs. price:

Click images to enlarge

The "big brand price" version (control) won the challenge by "so much that had the losing variation been rolled out without testing first, it would have cost the company hundreds of thousands of dollars in revenues per year." The test accounted for both online and telephone conversions.

At the time of writing, 63% of marketers voted for the social proof version...

Another example comes from DIYthemes.com:

The middle version without social proof converted at 2%, the alternate versions at 1% and 0.9%, respectively.

The secret to social proof

Depends on...


Both experiment results, upon closer examination, are not so surprising when you consider the context. It comes down to the user's primary motivator or primary FUD. FUD meaning fear, uncertainty or doubt.

Moneysupermarket.com users likely would appreciate knowing how other users rate sellers. But ultimately, the customer wants to get the best deal. It's not that social proof is not important, it's just not as much of a motivator as saving the most money.

In the case of DIYthemes, how big your marketing list is is irrelevant. Subscribers are more concerned about email privacy. A follow-up test with an anti-spam callout could outperform, with or without social proof. (Screenshots via KISSmetrics).

Whether you are using testimonials, fan counts, Like badges, or star ratings - ask yourself if there isn't a more important influencer of trust and action than social proof.


DIYthemes' case may demonstrate how design affects conversion. Simplifying forms, reducing text, making things look easy all aid in conversion. Again, further testing (including challenging social proof against privacy) is required to answer these questions.

Putting the proof in social proof

The post-modern, post-marketing consumer is skeptical. Certain forms of social proof are more trustworthy, and therefore can have a higher impact on conversion. For example, testimonials that link back to a customer website is more believable than anonymized praise, like from "--Judy, Ohio." Facebook and Twitter counts are verified by a third party, where simply throwing a number up on a site is not backed up by anything.

Bottom line

As each instalment of this series aims to illustrate, it's the application of so-called "best practice" that matters. Social proof may work, or may not work, and variables like context, design and type of social proof affect the results you will get.

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