• 42
• Reviews have been deleted

We discovered a total of 42 deleted Reviews for this product, with an average rating of 9.7. 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 our Deleted Reviews test.

Show distribution of deleted reviews

• 
• 42%
• Created over 20 days

We counted 434 reviews for this product over the span of 855 days, an average of 0.5 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 20 days exceeding this threshold:

• 20 Reviews on Feb 10, 2015 (Avg. rating: 9.3)
• 16 Reviews on Jun 19, 2015 (Avg. rating: 9.6)
• 15 Reviews on Jun 20, 2015 (Avg. rating: 9.5)
• 14 Reviews on Feb 5, 2015 (Avg. rating: 9.1)
• 10 Reviews on Feb 24, 2015 (Avg. rating: 9.5)
• 10 Reviews on Mar 10, 2015 (Avg. rating: 9.5)
• 9 Reviews on Jun 24, 2015 (Avg. rating: 9.6)
• 9 Reviews on Jun 15, 2015 (Avg. rating: 9.0)
• 9 Reviews on Mar 3, 2015 (Avg. rating: 8.7)
• 9 Reviews on Jun 26, 2015 (Avg. rating: 8.4)
• 9 Reviews on Jul 20, 2015 (Avg. rating: 8.3)
• 7 Reviews on Feb 17, 2015 (Avg. rating: 9.3)
• 7 Reviews on Jul 8, 2015 (Avg. rating: 9.0)
• 7 Reviews on Jun 18, 2015 (Avg. rating: 8.7)
• 6 Reviews on Jan 23, 2015 (Avg. rating: 9.8)
• 6 Reviews on Jun 27, 2015 (Avg. rating: 9.7)
• 6 Reviews on Jul 9, 2015 (Avg. rating: 9.7)
• 5 Reviews on Jun 21, 2015 (Avg. rating: 9.6)
• 5 Reviews on Jun 22, 2015 (Avg. rating: 9.0)
• 5 Reviews on Jul 7, 2015 (Avg. rating: 8.2)
Show All

In total, we found that 184 reviews were created on just 20 days. The reviews on these high volume days have rated this product an average of 9.2 while reviews from other days have rated this product an average of 8.6. 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.

• 
• 76%
• Unverified Purchases

332 of the 434 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 9.1 while the verified purchasers have rated this product an average of 8.1. 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

• 
• 64%
• Reviewed other products from this brand

278 of the 434 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, the discrepancy in ratings between the Brand Repeaters and non-repeaters isn't significant enough to rule out the possibility of it being due to random chance.

Brand Loyalists

• 
• 38%
• Reviewed mostly products from this brand

164 of the 434 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

• 
• 17%
• Reviewed only products from this brand

72 of the 434 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

• 
• 15%
• have only posted one review

65 of the 434 reviewers have only reviewed this product. While this is more One-Hit Wonders than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Never-Verified Reviewers

• 
• 57%
• have zero verified purchases

247 of the 434 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 9.1 while the reviewers who have written at least one verified purchase review rated this product an average of 8.5. 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.

Take-Back Reviewers

• 
• 21%
• have previously deleted reviews

91 of the 434 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.

Single-Day Reviewers

• 
• 17%
• have posted all their reviews on a single day

74 of the 434 reviewers have written multiple reviews but posted all of them on a single day. The Single-Day reviewers have rated this product an average of 9.1 while all other reviewers rated this product an average of 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.

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, 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.

• 
• 45%
• Substantial overlapping review history

196 of the 434 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 9.2 while the reviewers who have a more unique product review history rated this product an average of 8.6. 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.

• 
• 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.

• 
• 10%
• Used substantial repetitive phrases

42 of the 434 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.

• 
• 4%
• Mentioned the word "Sample"

16 of the 434 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.