• 990
• Reviews have been deleted

We discovered a total of 990 deleted reviews for this product, with an average rating of 4.7. 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 the Deleted Reviews test here.

Show distribution of deleted reviews

• 
• 44%
• Unverified Purchases

359 of the 819 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.6 while the verified purchasers have rated this product an average of 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.

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

• 
• 47%
• Reviewed other products from this brand

387 of the 819 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

• 
• 15%
• Reviewed mostly products from this brand

121 of the 819 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

• 
• 8%
• Reviewed only products from this brand

68 of the 819 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

122 of the 819 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

• 
• 15%
• have zero verified purchases

124 of the 819 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 4.6 while the reviewers who have written at least one verified purchase review rated this product an average of 4.4. 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

• 
• 29%
• have previously deleted reviews

236 of the 819 reviewers have had at least one of their past reviews for another product deleted. The Take-Back Reviewers have rated this product an average of 4.6 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 4.4. 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.

• 
• 3%
• Used substantial repetitive phrases

26 of the 819 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.8 while reviews without substantial repetitive phrases rated this product an average of 4.5. 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 Phrase Repetition test.

• 
• 21%
• Substantial overlapping review history

175 of the 819 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.6 while the reviewers who have a more unique product review history rated this product an average of 4.4. 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.

• 
• 12%
• Created over 17 days

We counted 819 reviews for this product over the span of 1,468 days, an average of 0.6 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 17 days exceeding this threshold:

• 11 reviews on Jan 30, 2016 (Avg. rating: 4.8)
• 7 reviews on Feb 1, 2016 (Avg. rating: 4.9)
• 6 reviews on Feb 7, 2016 (Avg. rating: 4.7)
• 6 reviews on Feb 8, 2016 (Avg. rating: 4.2)
• 6 reviews on Jan 10, 2016 (Avg. rating: 3.8)
• 5 reviews on Jul 27, 2015 (Avg. rating: 5.0)
• 5 reviews on Nov 21, 2015 (Avg. rating: 4.8)
• 5 reviews on Jan 11, 2016 (Avg. rating: 4.8)
• 5 reviews on Jan 13, 2016 (Avg. rating: 4.8)
• 5 reviews on Jul 6, 2015 (Avg. rating: 4.6)
• 5 reviews on Jan 26, 2016 (Avg. rating: 4.6)
• 5 reviews on Jan 28, 2016 (Avg. rating: 4.6)
• 5 reviews on Aug 14, 2015 (Avg. rating: 4.4)
• 5 reviews on Sep 2, 2015 (Avg. rating: 4.2)
• 5 reviews on May 6, 2015 (Avg. rating: 4.2)
• 5 reviews on Feb 29, 2016 (Avg. rating: 4.0)
• 5 reviews on Feb 17, 2016 (Avg. rating: 3.8)
Show All

In total, we found that 96 reviews were created on just 17 days. Although any days with a larger number of reviews than expected is suspicious, these reviews do not appear to have a significant impact on the overall rating.

Read more about our Rating Trend test.

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

• 
• 6%
• Admitted to receiving an incentive

51 of the 819 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. While we could not find a statistically significant difference between the average rating of incentivized reviews and non-incentivized reviews, the presences of at least one incentivized review indicates that there may be more, since not all reviewers will disclose that they had received an incentive to post a review.

Read more about our Incentivized Reviews test, or check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

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 4.5, while the average ease score for reviewers in this category is 4.4. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

• 
• 70%
• From reviewers with an overrepresented participation

We see the following 2 participation groups with a statistically significant greater concentration than what we'd expect to see:

• Reviewers with 1-5 reviews: 46.3% (Avg. rating: 4.5)
• Reviewers with 6-15 reviews: 23.9% (Avg. rating: 4.4)

In total, we found that 575 reviewers (or 70%) are within an overrepresented participation group. This is an excessively high number of reviewers in overrepresented participation groups.

Read more about our Reviewer Participation 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.