Quick answer
Products with five reviews were 3.7 times as likely to be purchased as products with none in Northwestern’s ecommerce research. A separate US survey found that 78% of respondents read more reviews for expensive products.
Northwestern’s Medill Spiegel Research Center
See the source and calculation. · Download the statistics and sources.
What changes when a product gets its first reviews?
Five reviews can answer questions that a star average cannot. Northwestern measured a large difference at the start of its review curve, then saw the gains from additional reviews diminish.
How much higher was purchase likelihood with five reviews?
Products with five reviews were 3.7 times as likely to be purchased as products with zero reviews in Northwestern’s study.
Northwestern examined ecommerce product data in its online reviews research. Research first published in 2017. Zobi calculation: Add the 270% relative increase to the no-review baseline of 1. This is the study’s relative comparison.
Northwestern’s Medill Spiegel Research Center · Link to this statistic
At what star ratings did purchase likelihood tend to peak?
Purchase likelihood tended to peak at 4.0 to 4.7 stars across categories in Northwestern’s study.
Northwestern examined ecommerce product data in its online reviews research. Research first published in 2017. A range observed in the study should not be treated as a target rating for an individual product.
Northwestern’s Medill Spiegel Research Center · Link to this statistic
What purchase odds did Northwestern report for verified buyer badges?
Northwestern reported 15% higher purchase odds when reviews were identified with a verified buyer badge.
Northwestern examined ecommerce product data in its online reviews research. Research first published in 2017. Odds and probability use different scales.
Northwestern’s Medill Spiegel Research Center · Link to this statistic
Why the price of the product matters
A customer buying an expensive item has more to verify. The conversion study and a later shopper survey measure that extra consideration in different ways.
How did the effect of displaying reviews differ by price?
In Northwestern’s study, displaying reviews was associated with a 190% relative conversion increase for lower-priced products and a 380% increase for higher-priced products.
Northwestern examined ecommerce product data in its online reviews research. Research first published in 2017. The comparison does not give the absolute conversion rate in either price group.
Northwestern’s Medill Spiegel Research Center · Link to this statistic
What does the reported review lift mean relative to each group’s baseline?
With each group’s no-review rate indexed to 1, the review-present rate was 2.9 for lower-priced products and 4.8 for higher-priced products in Northwestern’s study.
Northwestern examined ecommerce product data in its online reviews research. Research first published in 2017. Zobi calculation: Add 190% and 380% to each group’s own index of 1. The indexed values allow relative comparison only.
Northwestern’s Medill Spiegel Research Center · Link to this statistic
How many shoppers say they read more reviews for expensive products?
In PowerReviews’ 2023 survey, 78% of US respondents said they read more reviews for more expensive products.
PowerReviews surveyed 8,153 US consumers. 2023. The figure records what respondents said about their own shopping.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
What shoppers say they use reviews for
Text, ratings and customer photos answer different questions. The survey distinguishes reported influence on buying from the reasons people look for reviews in the first place.
How many consumers say ratings and reviews affect purchase decisions?
In PowerReviews’ 2023 survey, 93% of US respondents said ratings and reviews affected whether they purchased a product.
PowerReviews surveyed 8,153 US consumers. 2023. Self-reported influence is measured separately from actual conversion.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
How many consumers say they trust ratings and reviews when buying?
In PowerReviews’ 2023 survey, 91% of US respondents said they trusted ratings and reviews when making purchase decisions.
PowerReviews surveyed 8,153 US consumers. 2023. The survey does not establish trust in a specific retailer’s reviews.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
How many shoppers say customer imagery affects whether they buy?
In PowerReviews’ 2023 survey, 53% of US respondents said user-generated visual content affected whether they purchased a product.
PowerReviews surveyed 8,153 US consumers. 2023. The item covers customer visuals broadly.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
Who reads more when the purchase is unfamiliar?
A shopper replacing a familiar item faces a different decision from a shopper buying it for the first time. That difference gives a merchant a reason to start with products that raise the most questions.
Do shoppers read more reviews when a product is new to them?
In PowerReviews’ 2023 survey, 98% of US respondents said they were more likely to read reviews for a product they had never purchased.
PowerReviews surveyed 8,153 US consumers. 2023. The item asks about likelihood of reading reviews.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
How far apart were Gen Z and Boomers on reviews for expensive products?
In the PowerReviews survey, 83% of Gen Z respondents and 66% of Boomers said they read more reviews for expensive products, a 17-point gap.
PowerReviews surveyed 8,153 US consumers. 2023. Zobi calculation: Subtract the Boomer share of 66% from the Gen Z share of 83%. The displayed breakdown does not provide cohort counts beside these percentages.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
How often are reviews a way to discover unfamiliar products?
In PowerReviews’ 2023 survey, 74% of US respondents said ratings and reviews were a key way they learned about products they had never purchased.
PowerReviews surveyed 8,153 US consumers. 2023. The item asks about discovery. A separate item asks whether shoppers are more likely to read reviews before a new purchase.
PowerReviews’ 2023 US survey · PowerReviews’ 2023 US survey · Link to this statistic
How to use the comparisons
If a shopper asks a question the star average cannot answer, look at what the existing reviews actually say. Compare products by review coverage and price band, then check for recurring questions about fit, size or use. A product without reviews and a product with a long list of vague reviews need different work.
Sources, definitions and downloads
Northwestern’s research describes measured ecommerce behavior. PowerReviews’ 2023 methodology identifies 8,153 US consumers. The download separates the two and retains the original rate, comparison base and method for each statistic.
Sources and measurement context
How much higher was purchase likelihood with five reviews
Reported value: 3.7 times purchase likelihood.
Population: Northwestern examined ecommerce product data in its online reviews research.
Measurement period: Research first published in 2017.
Denominator: Purchase likelihood for products with zero reviews.
Limitations: This is the study’s relative comparison.
Read the original sourceAt what star ratings did purchase likelihood tend to peak
Reported value: 4.0–4.7 stars out of 5.
Population: Northwestern examined ecommerce product data in its online reviews research.
Measurement period: Research first published in 2017.
Denominator: Studied product categories and rating levels.
Limitations: A range observed in the study should not be treated as a target rating for an individual product.
Read the original sourceWhat purchase odds did Northwestern report for verified buyer badges
Reported value: 15 percent change in odds.
Population: Northwestern examined ecommerce product data in its online reviews research.
Measurement period: Research first published in 2017.
Denominator: Baseline purchase odds in the study comparison.
Limitations: Odds and probability use different scales.
Read the original sourceHow did the effect of displaying reviews differ by price
Reported value: 190 | 380 percent relative conversion increase.
Population: Northwestern examined ecommerce product data in its online reviews research.
Measurement period: Research first published in 2017.
Denominator: Each group’s own no-review conversion rate.
Limitations: The comparison does not give the absolute conversion rate in either price group.
Read the original sourceWhat does the reported review lift mean relative to each group’s baseline
Reported value: 2.9 | 4.8 baseline multiples.
Population: Northwestern examined ecommerce product data in its online reviews research.
Measurement period: Research first published in 2017.
Denominator: Within-price-group conversion with no reviews, indexed to 1.
Limitations: The indexed values allow relative comparison only.
Read the original sourceHow many shoppers say they read more reviews for expensive products
Reported value: 78 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the survey item.
Limitations: The figure records what respondents said about their own shopping.
Read the original sourceHow many consumers say ratings and reviews affect purchase decisions
Reported value: 93 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the survey item.
Limitations: Self-reported influence is measured separately from actual conversion.
Read the original sourceHow many consumers say they trust ratings and reviews when buying
Reported value: 91 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the survey item.
Limitations: The survey does not establish trust in a specific retailer’s reviews.
Read the original sourceHow many shoppers say customer imagery affects whether they buy
Reported value: 53 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the item on user-generated visual content.
Limitations: The item covers customer visuals broadly.
Read the original sourceDo shoppers read more reviews when a product is new to them
Reported value: 98 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the item about a product never purchased before.
Limitations: The item asks about likelihood of reading reviews.
Read the original sourceHow far apart were Gen Z and Boomers on reviews for expensive products
Reported value: 17 percentage points.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Gen Z and Boomer respondents in their own survey cohorts.
Limitations: The displayed breakdown does not provide cohort counts beside these percentages.
Read the original sourceHow often are reviews a way to discover unfamiliar products
Reported value: 74 percent.
Population: PowerReviews surveyed 8,153 US consumers.
Measurement period: 2023.
Denominator: Respondents to the discovery item.
Limitations: The item asks about discovery. A separate item asks whether shoppers are more likely to read reviews before a new purchase.
Read the original sourcePublisher disclosure
Zobi publishes this research and provides shopper conversation services for Shopify stores.
Review how Zobi handles shopper conversations for your store.
Start growing revenueAbout the author
Rene Siller is Head of New Bets at Zobi and oversees the research side of the site.