Mea culpa! I’ve been guilty of presenting exclusively positive testimonials in my marketing literature, CV and web sites. But we could improve our customer ratings by 20% if we include some bad reviews.

If your sales copy for your guest house, mobile app, professional services and products depend on customer reviews, you might be harming your marketing effectiveness by presenting unbalanced reviews.

Understandably, we want to put our best foot forward, make a good first impression, right?

But put yourself in your prospective customer’s shoes. In fact, think back to the last time you bought something for yourself. Something that needed saving up for. Something that you needed to be reliable, to do what it’s advertised to do. Chances are you didn’t rely on just the sales blurb, right?

I bet you scoured for reviews by previous customers. Did you make a big buying decision based on only positive reviews? Or did you check out a few complaints? Did you suss out the patterns of what typically goes wrong? Or see how the seller solved the problems, or not?

If I can’t find anything negative on the sales pages, I’ll explicitly google for complaints and reviews off the seller’s site. I’ve eliminated many high-budget items from my shortlist after sleuthing for rants and gripes.

There’s plenty research to prove how positive a few negative reviews can be. Have you noticed that Amazon highlights a positive and negative review? I’m sure Amazon A-B tests the crap out of their site, so surely it works, right?

But, why does it work?

In a paper by researchers at Chung-Ang University, Korea, the authors found that “…Providing consumers with positive information followed by a minor piece of negative information appears to enhance their overall evaluations of a target, relative to providing exclusively positive information.”

It’s about credibility. They summarise that “The credibility of web sites…can be damaged in the long run if all of the…messages are positive.”

Of course, once you allow a few complaints on your sales pages, don’t just leave them there! Respond as quickly as possible and try to resolve them.

Researchers at Queen’s University, Canada, reported that when complaints got responses, 38.7% of reviewers changed their rating after the response.

So what? Those changes resulted in a median increase of 1 star on a five-star grading scale. I.e. a massive 20% increase.

Nice to have a good star rating, but more importantly, negative reviews can show your prospective customers that you have nothing to hide and that you're responsive when something goes wrong.