Never-Verified Reviewers

• 
• 3%
• have zero verified purchases

30 of the 900 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 4.4. 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

• 
• 5%
• have previously deleted reviews

47 of the 900 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.

Read more about our Suspicious Reviewers 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 4.4, while the average ease score for reviewers in this category is 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.

• 
• 13%
• Created over 20 days

We counted 900 reviews for this product over the span of 2,116 days, an average of 0.4 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 4 or fewer reviews on any given day.

However, we see the following 20 days exceeding this threshold:

• 8 Reviews on Oct 20, 2016 (Avg. rating: 4.8)
• 8 Reviews on Apr 27, 2016 (Avg. rating: 4.1)
• 7 Reviews on Jul 15, 2016 (Avg. rating: 3.9)
• 6 Reviews on Aug 10, 2016 (Avg. rating: 5.0)
• 6 Reviews on Oct 28, 2016 (Avg. rating: 4.8)
• 6 Reviews on Oct 12, 2016 (Avg. rating: 4.7)
• 6 Reviews on Sep 2, 2016 (Avg. rating: 4.2)
• 6 Reviews on May 5, 2016 (Avg. rating: 4.0)
• 6 Reviews on Feb 9, 2017 (Avg. rating: 4.0)
• 5 Reviews on Apr 19, 2016 (Avg. rating: 5.0)
• 5 Reviews on Mar 29, 2016 (Avg. rating: 4.8)
• 5 Reviews on Nov 5, 2016 (Avg. rating: 4.8)
• 5 Reviews on Jan 2, 2017 (Avg. rating: 4.8)
• 5 Reviews on Aug 9, 2016 (Avg. rating: 4.6)
• 5 Reviews on Sep 26, 2016 (Avg. rating: 4.6)
• 5 Reviews on Mar 14, 2013 (Avg. rating: 4.4)
• 5 Reviews on Jan 16, 2014 (Avg. rating: 4.4)
• 5 Reviews on Sep 7, 2016 (Avg. rating: 4.4)
• 5 Reviews on Sep 16, 2016 (Avg. rating: 4.2)
• 5 Reviews on Jan 23, 2017 (Avg. rating: 4.0)
Show All

In total, we found that 114 reviews were created on just 20 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.

• 
• 52%
• Unverified Purchases

465 of the 900 total reviews for this product are unverified purchases. While this is a higher percentage of unverified purchases than we'd expect to see, the discrepancy in ratings between the unverified purchases and verified purchases isn't significant enough to rule out the possibility of it being due to random chance.

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.

• 
• 57%
• 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: 24.8% (Avg. rating: 4.4)
• Reviewers with 6-15 Reviews: 32.3% (Avg. rating: 4.5)

In total, we found that 514 reviewers (or 57%) 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.

• 
• 25%
• 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:

• 16-25 words: 25.4% (Avg. rating: 4.5)

In total, we found that 229 reviews (or 25%) 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.

• 
• 0%
• Used substantial repetitive phrases

1 of the 900 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.

• 
• 29%
• Substantial overlapping review history

264 of the 900 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.

Brand Repeaters

• 
• 19%
• Reviewed other products from this brand

170 of the 900 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

We didn't detect any reviews that used language indicating they were incentivized.
Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

• 0
• Reviews have been deleted

We have not discovered any deleted reviews for this product.

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.