• 1,284
• Reviews have been deleted

We discovered a total of 1,284 deleted Reviews for this product, with an average rating of 4.9. 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

• 
• 17%
• Created over 31 days

We counted 1,275 reviews for this product over the span of 1,717 days, an average of 0.7 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 5 or fewer reviews on any given day.

However, we see the following 31 days exceeding this threshold:

• 12 Reviews on Sep 8, 2016 (Avg. rating: 4.7)
• 12 Reviews on Sep 6, 2016 (Avg. rating: 4.7)
• 11 Reviews on Sep 7, 2016 (Avg. rating: 4.8)
• 10 Reviews on Aug 5, 2016 (Avg. rating: 4.5)
• 8 Reviews on Jul 18, 2016 (Avg. rating: 4.9)
• 8 Reviews on Jun 3, 2016 (Avg. rating: 4.1)
• 8 Reviews on Jul 25, 2016 (Avg. rating: 3.1)
• 7 Reviews on Jun 15, 2016 (Avg. rating: 4.9)
• 7 Reviews on Sep 5, 2016 (Avg. rating: 4.7)
• 7 Reviews on Jul 3, 2016 (Avg. rating: 4.6)
• 7 Reviews on Aug 11, 2016 (Avg. rating: 4.4)
• 7 Reviews on Aug 24, 2016 (Avg. rating: 4.0)
• 6 Reviews on Nov 2, 2016 (Avg. rating: 5.0)
• 6 Reviews on Jul 6, 2016 (Avg. rating: 5.0)
• 6 Reviews on Jul 8, 2016 (Avg. rating: 5.0)
• 6 Reviews on Jul 20, 2016 (Avg. rating: 4.8)
• 6 Reviews on Jul 16, 2016 (Avg. rating: 4.8)
• 6 Reviews on Jun 27, 2016 (Avg. rating: 4.7)
• 6 Reviews on Jun 16, 2016 (Avg. rating: 4.7)
• 6 Reviews on Aug 2, 2016 (Avg. rating: 4.3)
• 6 Reviews on Mar 18, 2016 (Avg. rating: 4.3)
• 6 Reviews on Sep 16, 2016 (Avg. rating: 4.3)
• 6 Reviews on Jul 7, 2016 (Avg. rating: 4.0)
• 6 Reviews on Jun 29, 2016 (Avg. rating: 4.0)
• 6 Reviews on Jun 9, 2016 (Avg. rating: 4.0)
• 6 Reviews on Aug 1, 2016 (Avg. rating: 3.8)
• 6 Reviews on Aug 14, 2016 (Avg. rating: 3.7)
• 6 Reviews on Jul 29, 2016 (Avg. rating: 3.5)
• 6 Reviews on Jul 13, 2016 (Avg. rating: 3.3)
• 6 Reviews on Jul 24, 2016 (Avg. rating: 3.0)
• 6 Reviews on Sep 17, 2015 (Avg. rating: 2.3)
Show All

In total, we found that 218 reviews were created on just 31 days. The reviews on these high volume days have rated this product an average of 4.3 while reviews from other days have rated this product an average of 4.0. 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.

Read more about our Rating Trend test.

• 
• 9%
• Unverified Purchases

110 of the 1,275 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.3 while the verified purchasers have rated this product an average of 4.0. 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.

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

• 
• 2%
• Admitted to receiving an incentive

25 of the 1,275 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. Incentivized reviews have rated this product an average of 4.6 while reviews that were not incentivized rated this product an average of 4.0. 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.

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

Never-Verified Reviewers

• 
• 1%
• have zero verified purchases

14 of the 1,275 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 4.7 while the reviewers who have written at least one verified purchase review rated this product an average of 4.0. 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.

Take-Back Reviewers

• 
• 42%
• have previously deleted reviews

539 of the 1,275 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 4.2 while the reviewers who don't have any deleted reviews in their history have 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 Suspicious Reviewers test.

• 
• 33%
• 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: 32.6% (Avg. rating: 3.9)

In total, we found that 416 reviewers (or 33%) 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.

• 
• 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.

• 
• 0%
• Used substantial repetitive phrases

1 of the 1,275 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.

• 
• 9%
• Substantial overlapping review history

109 of the 1,275 reviewers have substantial overlapping product review history. 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 Overlapping Review History 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 4.2, while the average ease score for reviewers in this category is 4.2.

Brand Repeaters

• 
• 2%
• Reviewed other products from this brand

21 of the 1,275 reviewers have reviewed other products for this brand. 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 Brand Repeats test.