• 151
• Reviews have been deleted

We discovered a total of 151 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

• 
• 20%
• Created over 14 days

We counted 322 reviews for this product over the span of 1,507 days, an average of 0.2 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:

• 7 Reviews on Jan 5, 2017 (Avg. rating: 5.0)
• 6 Reviews on Dec 22, 2016 (Avg. rating: 5.0)
• 6 Reviews on Feb 7, 2017 (Avg. rating: 4.7)
• 5 Reviews on Dec 31, 2016 (Avg. rating: 5.0)
• 5 Reviews on Jan 28, 2017 (Avg. rating: 5.0)
• 5 Reviews on Feb 3, 2017 (Avg. rating: 4.0)
• 4 Reviews on Dec 26, 2016 (Avg. rating: 5.0)
• 4 Reviews on Jan 2, 2017 (Avg. rating: 5.0)
• 4 Reviews on Jan 10, 2017 (Avg. rating: 5.0)
• 4 Reviews on Feb 6, 2017 (Avg. rating: 5.0)
• 4 Reviews on Feb 14, 2017 (Avg. rating: 5.0)
• 4 Reviews on Jan 9, 2017 (Avg. rating: 4.8)
• 4 Reviews on Feb 9, 2017 (Avg. rating: 4.5)
• 4 Reviews on Jan 16, 2017 (Avg. rating: 3.8)
Show All

In total, we found that 66 reviews were created on just 14 days. The reviews on these high volume days have rated this product an average of 4.8 while reviews from other days have 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 Rating Trend test.

• 
• 27%
• Unverified Purchases

87 of the 322 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.9 while the verified purchasers 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.

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

• 
• 60%
• have previously deleted reviews

193 of the 322 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.

• 
• 36%
• Substantial overlapping review history

117 of the 322 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.9 while the reviewers who have a more unique product review history 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.

Read more about our Overlapping Review History test.

Brand Repeaters

• 
• 43%
• Reviewed other products from this brand

139 of the 322 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.

Read more about our Brand Repeats 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.

• 
• 39%
• 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 31-50 Reviews: 18.6% (Avg. rating: 4.6)
• Reviewers with 51-100 Reviews: 19.9% (Avg. rating: 4.6)

In total, we found that 124 reviewers (or 39%) are within an overrepresented participation group. While this is more reviews from overrepresented participation groups than we'd expect to see, the discrepancy in ratings between reviewers in an overrepresented participation groups and all other reviewers isn’t significant enough to rule out the possibility of it being due to random chance.

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.

• 
• 2%
• Used substantial repetitive phrases

8 of the 322 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.

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

• 
• 1%
• Admitted to receiving an incentive

3 of the 322 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.