• 1,185
• Reviews have been deleted

We discovered a total of 1,185 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 our Deleted Reviews test.

Show distribution of deleted reviews

• 
• 46%
• Unverified Purchases

241 of the 528 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.7 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

• 
• 44%
• Reviewed other products from this brand

232 of the 528 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

• 
• 6%
• Reviewed mostly products from this brand

31 of the 528 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.

Read more about our Brand Repeats test.

Never-Verified Reviewers

• 
• 10%
• have zero verified purchases

51 of the 528 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 4.8 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

• 
• 37%
• have previously deleted reviews

197 of the 528 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 4.7 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.

• 
• 22%
• Substantial overlapping review history

118 of the 528 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.7 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.

• 
• 11%
• Created over 14 days

We counted 528 reviews for this product over the span of 1,823 days, an average of 0.3 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 3 or fewer reviews on any given day.

However, we see the following 14 days exceeding this threshold:

• 5 Reviews on Jun 2, 2016 (Avg. rating: 4.6)
• 5 Reviews on Sep 24, 2016 (Avg. rating: 4.4)
• 5 Reviews on Apr 13, 2016 (Avg. rating: 4.0)
• 5 Reviews on Aug 23, 2016 (Avg. rating: 4.0)
• 4 Reviews on Jul 1, 2015 (Avg. rating: 5.0)
• 4 Reviews on Feb 11, 2016 (Avg. rating: 5.0)
• 4 Reviews on Mar 2, 2016 (Avg. rating: 5.0)
• 4 Reviews on May 13, 2016 (Avg. rating: 5.0)
• 4 Reviews on Jan 28, 2016 (Avg. rating: 4.8)
• 4 Reviews on Feb 8, 2016 (Avg. rating: 4.8)
• 4 Reviews on Feb 28, 2016 (Avg. rating: 4.8)
• 4 Reviews on Jan 10, 2016 (Avg. rating: 4.5)
• 4 Reviews on Sep 19, 2015 (Avg. rating: 4.3)
• 4 Reviews on Sep 22, 2015 (Avg. rating: 4.3)
Show All

In total, we found that 60 reviews were created on just 14 days. Although any days with a larger number of reviews than expected is suspicious, the discrepancy in ratings from reviews created on these high volume days and reviews created on other days isn't significant enough to rule out the possibility of it being due to random chance.

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.

• 
• 7%
• Admitted to receiving an incentive

38 of the 528 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. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

• 
• 40%
• 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: 40.0% (Avg. rating: 4.4)

In total, we found that 211 reviewers (or 40%) are within an overrepresented participation group. While this is more reviews from overrepresented participation groups than we'd expect to see, these reviews do not appear to have a significant impact on the overall rating.

Read more about our Reviewer Participation test.

• 
• 19%
• 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:

• 101-200 words: 19.1% (Avg. rating: 4.6)

In total, we found that 101 reviews (or 19%) 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.

• 
• 8%
• Used substantial repetitive phrases

40 of the 528 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.

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.