• 
• 27%
• Created over 8 days

We counted 147 reviews for this product over the span of 1,400 days, an average of 0.1 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 2 or fewer reviews on any given day.

However, we see the following 8 days exceeding this threshold:

• 10 reviews on Feb 29, 2016 (Avg. rating: 10.0)
• 9 reviews on Mar 1, 2016 (Avg. rating: 10.0)
• 5 reviews on Sep 24, 2013 (Avg. rating: 9.6)
• 4 reviews on Sep 25, 2013 (Avg. rating: 9.5)
• 3 reviews on Mar 18, 2017 (Avg. rating: 10.0)
• 3 reviews on Sep 28, 2013 (Avg. rating: 9.7)
• 3 reviews on Oct 30, 2013 (Avg. rating: 9.7)
• 3 reviews on Oct 10, 2013 (Avg. rating: 9.0)
Show All

In total, we found that 40 reviews were created on just 8 days. The reviews on these high volume days have rated this product an average of 9.8 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.

• 
• 82%
• Unverified Purchases

121 of the 147 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 9.3 while the verified purchasers have rated this product an average of 7.0. 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.

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

• 
• 63%
• Reviewed other products from this brand

93 of the 147 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

• 
• 48%
• Reviewed mostly products from this brand

70 of the 147 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

• 
• 21%
• Reviewed only products from this brand

31 of the 147 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

• 
• 21%
• have only posted one review

31 of the 147 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

• 
• 65%
• have zero verified purchases

96 of the 147 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 9.3 while the reviewers who have written at least one verified purchase review 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.

Take-Back Reviewers

• 
• 18%
• have previously deleted reviews

27 of the 147 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

25 of the 147 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, the discrepancy in ratings between the Single-Day Reviewers and all other reviewers isn't significant enough to rule out the possibility of it being due to random chance.

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

66 of the 147 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 9.4 while the reviewers who have a more unique product review history 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.

Read more about our Overlapping Review History test.

• 
• 32%
• 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: 32.0% (Avg. rating: 9.4)

In total, we found that 47 reviewers (or 32%) are within an overrepresented participation group. These reviews have rated this product an average of 9.4, while all other reviews have rated this product an average of 8.7. 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 Reviewer Participation test.

• 4
• Reviews have been deleted

We discovered a total of 4 deleted reviews for this product, with an average rating of 9.5. 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

• 
• 5%
• Mentioned the word "Sample"

8 of the 147 total reviews for this product mentioned the word "sample" within their review. This is more than we would expect see; the presences of any reviews that mention the word "sample" indicates that there may be more, since not all reviewers will disclose that they used a sample within their review.

Read more about our Sample Reviews test.

• 
• 25%
• Used substantial repetitive phrases

37 of the 147 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.

• 
• 22%
• 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 1 group with a statistically significant greater concentration than what we'd expect to see:

• 66-100 words: 21.8% (Avg. rating: 9.2)

In total, we found that 32 reviews (or 22%) are within an overrepresented word count group. 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 Word Count Comparison test.