• 
• 20%
• Unverified Purchases

334 of the 1,668 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.3 while the verified purchasers have rated this product an average of 4.1. 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.

• 
• 51%
• 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: 16.7% (Avg. rating: 4.6)
• 6-15 words: 10.1% (Avg. rating: 4.3)
• 16-25 words: 23.9% (Avg. rating: 4.1)

In total, we found that 845 reviews (or 51%) are within an overrepresented word count group. These reviews have rated this product an average of 4.3, while all other reviews have rated this product an average of 3.5. 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 Word Count Comparison test.

• 
• 5%
• Used substantial repetitive phrases

87 of the 1,668 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.7 while reviews without substantial repetitive phrases rated this product an average of 3.9. 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 Phrase Repetition test.

• 
• 28%
• Substantial overlapping review history

475 of the 1,668 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.1 while the reviewers who have a more unique product review history rated this product an average of 3.9. 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.

• 
• 28%
• Created over 34 days

We counted 1,668 reviews for this product over the span of 1,411 days, an average of 1.2 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 6 or fewer reviews on any given day.

However, we see the following 34 days exceeding this threshold:

• 59 Reviews on Nov 29, 2017 (Avg. rating: 4.1)
• 31 Reviews on Nov 30, 2017 (Avg. rating: 3.9)
• 25 Reviews on Jan 10, 2018 (Avg. rating: 4.2)
• 22 Reviews on Apr 8, 2018 (Avg. rating: 4.0)
• 20 Reviews on Dec 19, 2017 (Avg. rating: 4.0)
• 19 Reviews on Nov 4, 2017 (Avg. rating: 3.2)
• 18 Reviews on Nov 5, 2017 (Avg. rating: 3.7)
• 15 Reviews on Nov 3, 2017 (Avg. rating: 2.9)
• 14 Reviews on Dec 3, 2017 (Avg. rating: 4.5)
• 13 Reviews on Nov 8, 2017 (Avg. rating: 3.8)
• 12 Reviews on Jan 14, 2018 (Avg. rating: 4.4)
• 12 Reviews on Nov 15, 2017 (Avg. rating: 4.2)
• 12 Reviews on Apr 9, 2018 (Avg. rating: 3.9)
• 12 Reviews on Nov 2, 2017 (Avg. rating: 2.8)
• 12 Reviews on Nov 19, 2017 (Avg. rating: 2.7)
• 11 Reviews on Nov 7, 2017 (Avg. rating: 4.5)
• 11 Reviews on Apr 7, 2018 (Avg. rating: 4.1)
• 10 Reviews on Jun 16, 2017 (Avg. rating: 4.6)
• 10 Reviews on Nov 11, 2017 (Avg. rating: 4.2)
• 10 Reviews on Dec 1, 2017 (Avg. rating: 3.9)
• 10 Reviews on Nov 6, 2017 (Avg. rating: 3.4)
• 10 Reviews on Apr 6, 2018 (Avg. rating: 2.7)
• 9 Reviews on Dec 4, 2017 (Avg. rating: 4.1)
• 9 Reviews on Nov 13, 2017 (Avg. rating: 3.8)
• 9 Reviews on Nov 12, 2017 (Avg. rating: 3.7)
• 9 Reviews on Jan 21, 2018 (Avg. rating: 3.2)
• 9 Reviews on Dec 2, 2017 (Avg. rating: 3.1)
• 8 Reviews on Jan 11, 2018 (Avg. rating: 3.5)
• 8 Reviews on Jan 22, 2018 (Avg. rating: 3.1)
• 8 Reviews on Dec 18, 2017 (Avg. rating: 3.0)
• 7 Reviews on Jun 15, 2017 (Avg. rating: 4.4)
• 7 Reviews on Jan 18, 2018 (Avg. rating: 3.7)
• 7 Reviews on Mar 30, 2018 (Avg. rating: 3.3)
• 7 Reviews on Jun 18, 2017 (Avg. rating: 3.1)
Show All

In total, we found that 465 reviews were created on just 34 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

Take-Back Reviewers

• 
• 28%
• have previously deleted reviews

471 of the 1,668 reviewers have had at least one of their past reviews for another product deleted. While this is more Take-Back Reviewers than we'd expect to see, the discrepancy in ratings between the Take-Back Reviewers and reviewers who don't have any deleted reviews in their history isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Suspicious Reviewers 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.

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 4.1, while the average ease score for reviewers in this category is 3.9. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

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.