Take-Back Reviewers

• 
• 31%
• have previously deleted reviews

2,198 of the 7,022 reviewers have had at least one of their past reviews for another product deleted. While this is more Take-Back Reviewers than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Single-Day Reviewers

• 
• 4%
• have posted all their reviews on a single day

268 of the 7,022 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 4.5 while all other reviewers rated this product an average of 4.2. 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.

• 
• 5%
• Used substantial repetitive phrases

361 of the 7,022 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.5 while reviews without substantial repetitive phrases rated this product an average of 4.2. 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.

• 339
• Reviews have been deleted

We discovered a total of 339 deleted reviews for this product, with an average rating of 4.3. 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

• 
• 6%
• Created over 49 days

We counted 7,022 reviews for this product over the span of 4,220 days, an average of 1.7 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 7 or fewer reviews on any given day.

However, we see the following 49 days exceeding this threshold:

• 11 reviews on Sep 14, 2015 (Avg. rating: 4.5)
• 11 reviews on May 4, 2016 (Avg. rating: 4.4)
• 10 reviews on Jul 29, 2019 (Avg. rating: 4.5)
• 10 reviews on Nov 10, 2015 (Avg. rating: 4.5)
• 10 reviews on Jul 19, 2017 (Avg. rating: 4.0)
• 10 reviews on Jan 9, 2019 (Avg. rating: 3.9)
• 10 reviews on Jul 6, 2018 (Avg. rating: 3.3)
• 9 reviews on Aug 26, 2019 (Avg. rating: 5.0)
• 9 reviews on May 29, 2019 (Avg. rating: 4.7)
• 9 reviews on Jan 22, 2016 (Avg. rating: 4.6)
• 9 reviews on Jul 26, 2017 (Avg. rating: 4.4)
• 9 reviews on Jun 19, 2019 (Avg. rating: 4.3)
• 9 reviews on Jun 26, 2019 (Avg. rating: 4.1)
• 9 reviews on Jul 7, 2019 (Avg. rating: 4.0)
• 9 reviews on Jul 25, 2015 (Avg. rating: 4.0)
• 9 reviews on Nov 19, 2015 (Avg. rating: 3.8)
• 9 reviews on Jul 25, 2018 (Avg. rating: 3.8)
• 9 reviews on Mar 19, 2018 (Avg. rating: 3.6)
• 9 reviews on Aug 12, 2018 (Avg. rating: 3.6)
• 9 reviews on Apr 21, 2016 (Avg. rating: 3.6)
• 9 reviews on Apr 6, 2018 (Avg. rating: 3.1)
• 8 reviews on Jul 14, 2018 (Avg. rating: 5.0)
• 8 reviews on Jun 25, 2019 (Avg. rating: 5.0)
• 8 reviews on Jun 30, 2019 (Avg. rating: 5.0)
• 8 reviews on Jul 12, 2019 (Avg. rating: 5.0)
• 8 reviews on Mar 25, 2015 (Avg. rating: 5.0)
• 8 reviews on Mar 29, 2016 (Avg. rating: 5.0)
• 8 reviews on Jul 30, 2019 (Avg. rating: 4.9)
• 8 reviews on Feb 18, 2016 (Avg. rating: 4.9)
• 8 reviews on May 2, 2016 (Avg. rating: 4.9)
• 8 reviews on Jun 10, 2016 (Avg. rating: 4.9)
• 8 reviews on Jul 20, 2017 (Avg. rating: 4.9)
• 8 reviews on Jan 16, 2018 (Avg. rating: 4.9)
• 8 reviews on Jun 26, 2017 (Avg. rating: 4.8)
• 8 reviews on Dec 10, 2018 (Avg. rating: 4.6)
• 8 reviews on Mar 31, 2015 (Avg. rating: 4.5)
• 8 reviews on May 17, 2018 (Avg. rating: 4.5)
• 8 reviews on Jul 1, 2015 (Avg. rating: 4.4)
• 8 reviews on May 2, 2018 (Avg. rating: 4.3)
• 8 reviews on Oct 8, 2015 (Avg. rating: 4.1)
• 8 reviews on Jul 5, 2017 (Avg. rating: 4.1)
• 8 reviews on Jul 1, 2018 (Avg. rating: 4.1)
• 8 reviews on Apr 27, 2016 (Avg. rating: 4.0)
• 8 reviews on Apr 11, 2018 (Avg. rating: 4.0)
• 8 reviews on Aug 16, 2017 (Avg. rating: 4.0)
• 8 reviews on Jan 10, 2018 (Avg. rating: 3.8)
• 8 reviews on Apr 3, 2018 (Avg. rating: 3.5)
• 8 reviews on Mar 21, 2018 (Avg. rating: 3.5)
• 8 reviews on Aug 10, 2015 (Avg. rating: 3.4)
Show All

In total, we found that 422 reviews were created on just 49 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.

• 
• 55%
• 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: 18.9% (Avg. rating: 4.1)
• Reviewers with 6-15 reviews: 36.0% (Avg. rating: 4.2)

In total, we found that 3858 reviewers (or 55%) 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.

• 
• 8%
• Unverified Purchases

585 of the 7,022 total reviews for this product are unverified purchases. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

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.

• 
• 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.

• 
• 4%
• Substantial overlapping review history

247 of the 7,022 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 4.3.

Brand Repeaters

• 
• 2%
• Reviewed other products from this brand

122 of the 7,022 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 7,022 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, or check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.