Never-Verified Reviewers

• 
• 86%
• have zero verified purchases

658 of the 769 reviewers have never written a verified purchase review. This is an excessively large percentage of Never-Verified Reviewers which may indicate unnatural reviews.

Single-Day Reviewers

• 
• 26%
• have posted all their reviews on a single day

197 of the 769 reviewers have written multiple reviews but posted all of them on a single day. While this is more Single-Day Reviewers than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Read more about our Suspicious Reviewers test.

The ease score is the average rating for all reviews that a given reviewer submits. The average ease score for reviewers of this product is 4.9, while the average ease score for reviewers in this category is 4.3. Based on our statistical modeling, the discrepancy in average rating between these two groups is significant enough to believe that the difference is not due to random chance, and may indicate that there are unnatural reviews.

• 
• 41%
• Created over 1 day

We counted 769 reviews for this product over the span of 4 days, an average of 192.3 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 231 or fewer reviews on any given day.

However, we see the following 1 day exceeding this threshold:

• 316 Reviews on Jan 8, 2019 (Avg. rating: 5.0)

In total, we found that 316 reviews were created on just 1 day. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 100%
• Unverified Purchases

769 of the 769 total reviews for this product are unverified purchases. This is an excessively large percentage of unverified purchases and it may indicate unnatural reviews.

Unverified purchases may be the result of Kindle Unlimited readers, buyers who didn't pay full price, or reviewers who did not purchase the product at Amazon. Read more about our Unverified Purchases test.

• 
• 93%
• Have an overrepresented word count

In the graph above, we can see the distribution of review word counts for this product and the expected distribution for this category. We see the following 3 groups with a statistically significant greater concentration than what we'd expect to see:

• 0-5 words: 26.4% (Avg. rating: 5.0)
• 6-15 words: 39.0% (Avg. rating: 5.0)
• 16-25 words: 27.7% (Avg. rating: 5.0)

In total, we found that 716 reviews (or 93%) are within an overrepresented word count group. This is an excessively high number of reviews in overrepresented word count groups.

Read more about our Word Count Comparison test.

• 
• 19%
• Used substantial repetitive phrases

147 of the 769 total reviews for this product use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Phrase Repetition test.

• 
• 100%
• Substantial overlapping review history

769 of the 769 reviewers have substantial overlapping product review history. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Overlapping Review History test.

• 
• 33%
• From reviewers with an overrepresented participation

We see the following 1 participation group with a statistically significant greater concentration than what we'd expect to see:

• Reviewers with 6-15 Reviews: 33.3% (Avg. rating: 5.0)

In total, we found that 256 reviewers (or 33%) are within an overrepresented participation group. While this is more reviews from overrepresented participation groups than we'd expect to see, these reviews do not appear to have a significant impact on the overall rating.

Read more about our Reviewer Participation test.

Brand Repeaters

We didn't detect a substantial amount of Brand Repeaters.

On Oct 3, 2016, Amazon prohibited incentivized reviews, however we still test for them since there are still millions in our dataset.

• 
• 0%
• Admitted to receiving an incentive

We didn't detect any reviews that used language indicating they were incentivized.
Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

• 0
• Reviews have been deleted

We have not discovered any deleted reviews for this product.

There are a few limitations to keep in mind regarding the Deleted Reviews test:

1. We don't have a magic ability to collect every single deleted review; we can only identify reviews as deleted if we collect them on one date and then notice they are no longer visible on a subsequent date.
2. We have no information on reviews that were never published in the first place.
3. We also don't know why these reviews were removed. It could be action from the platform, personal decision by the review author, part of an entire account closure, even some data error on our part, etc.

Read more about our Deleted Reviews test.