• 
• 45%
• Unverified Purchases

159 of the 356 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 1.9 while the verified purchasers have rated this product an average of 3.4. 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.

Never-Verified Reviewers

• 
• 11%
• have zero verified purchases

39 of the 356 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 2.0 while the reviewers who have written at least one verified purchase review rated this product an average of 2.8. 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.

Take-Back Reviewers

• 
• 10%
• have previously deleted reviews

37 of the 356 reviewers have had at least one of their past reviews for another product deleted. This is an excessively large percentage of Take-Back Reviewers which may indicate unnatural reviews.

Read more about our Suspicious Reviewers test.

• 
• 23%
• Created over 25 days

We counted 356 reviews for this product over the span of 2,755 days, an average of 0.1 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 2 or fewer reviews on any given day.

However, we see the following 25 days exceeding this threshold:

• 6 Reviews on Dec 3, 2009 (Avg. rating: 2.5)
• 5 Reviews on Oct 16, 2009 (Avg. rating: 3.0)
• 4 Reviews on Nov 18, 2009 (Avg. rating: 3.3)
• 4 Reviews on Oct 15, 2009 (Avg. rating: 3.0)
• 4 Reviews on Feb 6, 2010 (Avg. rating: 1.3)
• 3 Reviews on Dec 5, 2009 (Avg. rating: 4.3)
• 3 Reviews on Dec 28, 2009 (Avg. rating: 4.3)
• 3 Reviews on Jul 1, 2010 (Avg. rating: 4.0)
• 3 Reviews on Dec 19, 2009 (Avg. rating: 3.7)
• 3 Reviews on May 1, 2010 (Avg. rating: 3.7)
• 3 Reviews on Aug 29, 2010 (Avg. rating: 3.7)
• 3 Reviews on Jan 10, 2010 (Avg. rating: 3.0)
• 3 Reviews on Jan 21, 2010 (Avg. rating: 3.0)
• 3 Reviews on Feb 24, 2010 (Avg. rating: 2.7)
• 3 Reviews on Mar 28, 2010 (Avg. rating: 2.7)
• 3 Reviews on Jan 30, 2010 (Avg. rating: 2.3)
• 3 Reviews on Feb 20, 2010 (Avg. rating: 2.3)
• 3 Reviews on Feb 21, 2010 (Avg. rating: 2.0)
• 3 Reviews on Aug 23, 2010 (Avg. rating: 2.0)
• 3 Reviews on Feb 22, 2010 (Avg. rating: 1.3)
• 3 Reviews on Mar 6, 2010 (Avg. rating: 1.3)
• 3 Reviews on Mar 20, 2010 (Avg. rating: 1.3)
• 3 Reviews on Nov 15, 2009 (Avg. rating: 1.0)
• 3 Reviews on Jan 20, 2010 (Avg. rating: 1.0)
• 3 Reviews on May 25, 2010 (Avg. rating: 1.0)
Show All

In total, we found that 83 reviews were created on just 25 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 23%
• Used substantial repetitive phrases

83 of the 356 total reviews for this product use substantial repetitive phrases between them. While this is more than we'd expect to see, the discrepancy in ratings between the these reviews and reviews without substantial repetitive phrases isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Phrase Repetition test.

• 
• 69%
• 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: 40.5% (Avg. rating: 2.5)
• Reviewers with 6-15 Reviews: 28.1% (Avg. rating: 2.9)

In total, we found that 244 reviewers (or 69%) 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.

• 
• 28%
• 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:

• 101-200 words: 27.8% (Avg. rating: 2.2)

In total, we found that 99 reviews (or 28%) 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.

• 
• 12%
• Substantial overlapping review history

42 of the 356 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 3.7, while the average ease score for reviewers in this category is 4.3.

Brand Repeaters

• 
• 10%
• Reviewed other products from this brand

35 of the 356 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.