• 
• 18%
• Unverified Purchases

664 of the 3,775 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 1.0 while the verified purchasers 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.

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.

One-Hit Wonders

• 
• ~15%
• have only posted one review

Approximately 15% of reviewers have only reviewed this product. While this is more One-Hit Wonders than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Never-Verified Reviewers

• 
• <10%
• have zero verified purchases

Less than approximately 10% of reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 1.0 while the reviewers who have written at least one verified purchase review rated this product an average of 3.5. 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.

Take-Back Reviewers

• 
• <10%
• have previously deleted reviews

Less than approximately 10% of 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.

• 
• ~50%
• Created on high-volume days

It appears that several reviews were created during just a short period of time.
Read more about our Rating Trend test.

• 
• <10%
• Used substantial repetitive phrases

Less than approximately 10% of reviews use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Phrase Repetition test.

• 
• <10%
• 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.

• 
• ~15%
• Substantial overlapping review history

Approximately 15% of 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 3.9, while the average ease score for reviewers in this category is 4.2.

Brand Repeaters

We didn't detect a substantial amount of Brand Repeaters.

We examined the average net helpfulness score of negative reviews against the average net helpfulness score of positive reviews. The net helpfulness score is the number of times a review has been marked as helpful minus the number of times a review has been marked as unhelpful. We could not find any statistically significant difference in average net helpfulness score between the negative reviews and positive reviews.

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

• 
• <10%
• 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, or check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

We haven't collected sufficient data to run this test yet. See more