• 138
• Reviews have been deleted

We discovered a total of 138 deleted Reviews for this product, with an average rating of 4.5. 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 our Deleted Reviews test.

Show distribution of deleted reviews

• 
• 7%
• Created over 23 days

We counted 2,577 reviews for this product over the span of 2,518 days, an average of 1.0 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 6 or fewer reviews on any given day.

However, we see the following 23 days exceeding this threshold:

• 14 Reviews on Nov 15, 2017 (Avg. rating: 4.6)
• 14 Reviews on Nov 14, 2017 (Avg. rating: 4.3)
• 10 Reviews on Dec 27, 2016 (Avg. rating: 4.2)
• 10 Reviews on Mar 2, 2016 (Avg. rating: 3.9)
• 9 Reviews on Dec 30, 2016 (Avg. rating: 4.9)
• 9 Reviews on Jan 2, 2017 (Avg. rating: 4.7)
• 8 Reviews on Dec 9, 2016 (Avg. rating: 4.4)
• 8 Reviews on Dec 12, 2016 (Avg. rating: 4.3)
• 7 Reviews on Aug 18, 2015 (Avg. rating: 4.9)
• 7 Reviews on Dec 10, 2016 (Avg. rating: 4.9)
• 7 Reviews on Dec 31, 2016 (Avg. rating: 4.7)
• 7 Reviews on Feb 23, 2017 (Avg. rating: 4.7)
• 7 Reviews on Jan 4, 2016 (Avg. rating: 4.6)
• 7 Reviews on May 18, 2016 (Avg. rating: 4.6)
• 7 Reviews on Aug 25, 2015 (Avg. rating: 4.4)
• 7 Reviews on Mar 1, 2016 (Avg. rating: 4.4)
• 7 Reviews on Jan 21, 2017 (Avg. rating: 4.3)
• 7 Reviews on Nov 28, 2015 (Avg. rating: 4.1)
• 7 Reviews on Dec 16, 2016 (Avg. rating: 4.1)
• 7 Reviews on Dec 19, 2016 (Avg. rating: 4.0)
• 7 Reviews on Jan 20, 2016 (Avg. rating: 3.9)
• 7 Reviews on Feb 26, 2016 (Avg. rating: 3.7)
• 7 Reviews on Jan 28, 2017 (Avg. rating: 3.1)
Show All

In total, we found that 187 reviews were created on just 23 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.

• 
• 6%
• Unverified Purchases

165 of the 2,577 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.3 while the verified purchasers have rated this product an average of 4.1. 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.

Take-Back Reviewers

• 
• 44%
• have previously deleted reviews

1,127 of the 2,577 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 4.1 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.

Single-Day Reviewers

• 
• 3%
• have posted all their reviews on a single day

82 of the 2,577 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 4.4 while all other reviewers 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 Suspicious Reviewers test.

• 
• 26%
• 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:

• 0-5 words: 26.4% (Avg. rating: 4.5)

In total, we found that 680 reviews (or 26%) are within an overrepresented word count group. These reviews have rated this product an average of 4.5, while all other reviews have rated this product an average of 3.8. 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 Word Count Comparison test.

• 
• 10%
• Substantial overlapping review history

250 of the 2,577 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.2 while the reviewers who have a more unique product review history 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 Overlapping Review History test.

• 
• 0%
• Used substantial repetitive phrases

0 of the 2,577 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.

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 4.1, while the average ease score for reviewers in this category is 4.2.

Brand Repeaters

• 
• 11%
• Reviewed other products from this brand

277 of the 2,577 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.

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

• 
• 0%
• Admitted to receiving an incentive

2 of the 2,577 total reviews for this product admitted to receiving a free or discounted product in exchange for a 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 Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.