Star Ratings and Review Content

How Do Star Ratings and Review Content Influence Purchase?


Using data supplied by PowerReviews, a company that works with global brands & retailers to collect and display customer ratings and reviews, the Medill Spiegel Research Center analyzed how star ratings and online reviews influence purchase.


It’s largely understood that ratings and reviews play a big role in consumers’ purchase decisions. In fact, previous PowerReviews survey research found that the presence of ratings and reviews is one of the top factors impacting purchase decisions—second only to price. But what’s less obvious are the circumstances under which reviews have the biggest impact on purchase. This research analyzed the impact of reviews on purchase, by analyzing customer data, and aims to better understand the influence of ratings and reviews as a whole and the impact and role various review elements play on sales.

Spiegel Insight Proof Action Items for Marketers

Negative reviews establish trust.

Across more than 40 categories analyzed, purchase likelihood peaks when the average star rating of a product is between 4.2 and 4.5 stars and starts to drop as the star rating approaches a perfect 5. As counterintuitive as it may seem, negative reviews have a positive impact because they help establish trust and authenticity. In fact, previous PowerReviews research found that 82 percent of shoppers specifically seek out negative reviews.
Embrace negative reviews. While you certainly don’t want to aim for negative reviews, allowing them on your site brings authenticity to your review content and helps you build trust with shoppers, especially because the vast majority of consumers are actively seeking out negative reviews.
Reviews matter impact sales more for higher priced items.
Our team studied the effects of star ratings on low and high priced products within the same category—even a relatively low priced category like hair care products. We segmented products within each category into low-priced and high-priced items and found that star ratings had a stronger influence on expensive items compared to the cheaper items within the same category.
Make getting reviews for higher priced items a priority. There’s a higher risk involved with purchasing a higher priced item. Reviews can help consumers overcome this risk.

Star ratings have greater influence in high-consideration categories. High consideration categories could include items that are expensive, involve safety or are an unknown product or brand.

The study found that star ratings are most impactful for expensive products within high consideration categories, because reviews mitigate risk. When a consumer has less information about a category or product, such as a new brand or one that is higher priced within its category (think organic), more information — in the form of reviews — will lead to a greater likelihood to buy it.

Reviews, then, can be especially important when launching new products. Consider sampling for new brands or products. Reviews matter when the likelihood of a consumer purchasing a product is inherently low.

This is especially true when a brand or product is relatively unknown, or when the product is completely new in an existing category. When a new product or brand is launched into an existing category, it makes sense , then, to actively seek out reviews from consumers. Product sampling can allow brands to generate reviews for new products, which can mitigate risk for future buyers and lead to more sales.

When reviews are shorter, more is better.

The ideal number of reviews depends on the length of the reviews themselves. When reviews are shorter, more reviews matter. When reviews are longer, however, the number of reviews has a less significant impact.

Generate more reviews. The number of reviews for a product can have an impact on sales, especially if those reviews are short. Take a look at your reviews data, and identify products where reviews are generally short. Studies show that up to 80 percent of reviews originate from post-purchase emails, so be sure to send an email to shoppers asking them to review their purchases. Make the process as simple as possible to generate the most reviews.

Academic Publications

Feedback or Questions?

Learn about all the opportunities in SRC and how you can be engaged with our research projects.
Skip to content