• 
• 23%
• Unverified Purchases

200 of the 880 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.6 while the verified purchasers 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.

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.

Never-Verified Reviewers

• 
• 8%
• have zero verified purchases

70 of the 880 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 3.5 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

• 
• 4%
• have previously deleted reviews

37 of the 880 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

• 
• 7%
• have posted all their reviews on a single day

59 of the 880 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 4.7 while all other reviewers 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 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 4.3, while the average ease score for reviewers in this category is 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.

• 
• 30%
• 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: 30.0% (Avg. rating: 4.6)

In total, we found that 264 reviews (or 30%) are within an overrepresented word count group. These reviews have rated this product an average of 4.6, while all other reviews have 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 Word Count Comparison test.

• 
• 34%
• Used substantial repetitive phrases

302 of the 880 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.

• 
• 17%
• Created over 22 days

We counted 880 reviews for this product over the span of 1,343 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 22 days exceeding this threshold:

• 11 Reviews on May 3, 2014 (Avg. rating: 4.3)
• 8 Reviews on Mar 29, 2014 (Avg. rating: 4.6)
• 8 Reviews on Mar 30, 2014 (Avg. rating: 4.6)
• 8 Reviews on Apr 15, 2014 (Avg. rating: 4.3)
• 8 Reviews on Apr 3, 2014 (Avg. rating: 3.9)
• 7 Reviews on Apr 28, 2014 (Avg. rating: 4.7)
• 7 Reviews on Apr 1, 2014 (Avg. rating: 4.6)
• 7 Reviews on May 7, 2014 (Avg. rating: 4.6)
• 7 Reviews on Apr 22, 2014 (Avg. rating: 4.4)
• 7 Reviews on May 1, 2014 (Avg. rating: 4.4)
• 7 Reviews on Apr 10, 2014 (Avg. rating: 3.9)
• 6 Reviews on Apr 24, 2014 (Avg. rating: 5.0)
• 6 Reviews on Apr 19, 2014 (Avg. rating: 4.8)
• 6 Reviews on May 11, 2014 (Avg. rating: 4.8)
• 6 Reviews on May 14, 2014 (Avg. rating: 4.8)
• 6 Reviews on May 16, 2014 (Avg. rating: 4.8)
• 6 Reviews on Jun 10, 2014 (Avg. rating: 4.8)
• 6 Reviews on Apr 26, 2014 (Avg. rating: 4.7)
• 6 Reviews on Apr 4, 2014 (Avg. rating: 4.5)
• 6 Reviews on Apr 30, 2014 (Avg. rating: 4.5)
• 6 Reviews on Apr 7, 2014 (Avg. rating: 4.0)
• 6 Reviews on Mar 28, 2014 (Avg. rating: 3.3)
Show All

In total, we found that 151 reviews were created on just 22 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 21%
• Substantial overlapping review history

188 of the 880 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.

• 
• 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.

Brand Repeaters

• 
• 0%
• Reviewed other products from this brand

4 of the 880 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.