• 
• 20%
• Created over 13 days

We counted 453 reviews for this product over the span of 1,191 days, an average of 0.4 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 4 or fewer reviews on any given day.

However, we see the following 13 days exceeding this threshold:

• 15 reviews on Feb 21, 2017 (Avg. rating: 9.6)
• 12 reviews on Jan 13, 2017 (Avg. rating: 9.4)
• 11 reviews on Jun 19, 2014 (Avg. rating: 9.2)
• 7 reviews on Mar 20, 2017 (Avg. rating: 9.1)
• 6 reviews on Nov 21, 2016 (Avg. rating: 9.8)
• 5 reviews on Nov 18, 2016 (Avg. rating: 10.0)
• 5 reviews on Mar 16, 2017 (Avg. rating: 9.8)
• 5 reviews on Mar 22, 2017 (Avg. rating: 9.8)
• 5 reviews on Aug 20, 2015 (Avg. rating: 9.6)
• 5 reviews on May 1, 2017 (Avg. rating: 9.6)
• 5 reviews on Jan 15, 2017 (Avg. rating: 9.4)
• 5 reviews on Jan 27, 2017 (Avg. rating: 9.4)
• 5 reviews on Mar 17, 2017 (Avg. rating: 9.4)
Show All

In total, we found that 91 reviews were created on just 13 days. The reviews on these high volume days have rated this product an average of 9.5 while reviews from other days have rated this product an average of 9.2. 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.

Read more about our Rating Trend test.

• 
• 60%
• Unverified Purchases

271 of the 453 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 9.4 while the verified purchasers have rated this product an average of 9.1. 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.

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.

Brand Repeaters

• 
• 32%
• Reviewed other products from this brand

146 of the 453 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Brand Loyalists

• 
• 20%
• Reviewed mostly products from this brand

90 of the 453 reviewers have reviewed multiple products but half or more of their reviews are for this brand. This is an excessively large percentage of Brand Loyalists which may indicate unnatural reviews.

Brand Monogamists

• 
• 3%
• Reviewed only products from this brand

15 of the 453 reviewers have reviewed multiple products, but only for this brand. This is an excessively large percentage of Brand Monogamists which may indicate unnatural reviews.

Read more about our Brand Repeats test.

One-Hit Wonders

• 
• 31%
• have only posted one review

139 of the 453 reviewers have only reviewed this product. This is an excessively large percentage of One-Hit Wonders which may indicate unnatural reviews.

Never-Verified Reviewers

• 
• 46%
• have zero verified purchases

208 of the 453 reviewers have never written a verified purchase review. While this is more Never-Verified Reviewers than we'd expect to see, the discrepancy in ratings between the Never-Verified Reviewers and reviewers who have written at least one verified purchase review isn't significant enough to rule out the possibility of it being due to random chance.

Take-Back Reviewers

• 
• 17%
• have previously deleted reviews

78 of the 453 reviewers have had at least one of their past reviews for another product deleted. This is an excessively large percentage of Take-Back Reviewers which may indicate unnatural reviews.

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 9.1, while the average ease score for reviewers in this category is 8.8. 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.

• 
• 48%
• Substantial overlapping review history

217 of the 453 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 9.6 while the reviewers who have a more unique product review history rated this product an average of 9.0. 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.

Read more about our Overlapping Review History test.

• 11
• Reviews have been deleted

We discovered a total of 11 deleted reviews for this product, with an average rating of 9.4. Even though deleted reviews don't affect the average rating, the fact that action was taken to delete reviews raises some red flags about the integrity of the reviews for the product as whole.

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 the Deleted Reviews test here.

Show distribution of deleted reviews

• 
• 0%
• Have an overrepresented word count

We didn't find any review word count groups that had a statistically significant greater concentration than what we'd expect to see in this category.
Read more about our Word Count Comparison test.

• 
• 7%
• Used substantial repetitive phrases

33 of the 453 total reviews for this product use substantial repetitive phrases between them. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

Read more about our Phrase Repetition test.

• 
• 0%
• From reviewers with an overrepresented participation

We didn't find any participation groups that had a statistically significant greater concentration than what we'd expect to see in this category.
Read more about our Reviewer Participation test.

• 
• 3%
• Mentioned the word "Sample"

14 of the 453 total reviews for this product mentioned the word "sample" within their review. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

Read more about our Sample Reviews test.