• 
• 57%
• Unverified Purchases

369 of the 645 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.3 while the verified purchasers have rated this product an average of 4.1. 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

• 
• 6%
• have only posted one review

40 of the 645 reviewers have only reviewed this product. The One-Hit Wonders have rated this product an average of 4.1 while the reviewers who have posted more than one review have rated this product an average of 3.6. 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

• 
• 18%
• have previously deleted reviews

114 of the 645 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.

• 
• 46%
• 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: 22.5% (Avg. rating: 4.0)
• Reviewers with 6-15 Reviews: 23.3% (Avg. rating: 3.7)

In total, we found that 295 reviewers (or 46%) are within an overrepresented participation group. These reviews have rated this product an average of 3.8, while all other reviews have 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.

Read more about our Reviewer Participation test.

• 
• 22%
• Created over 29 days

We counted 645 reviews for this product over the span of 4,274 days, an average of 0.2 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 29 days exceeding this threshold:

• 14 Reviews on Jul 22, 2006 (Avg. rating: 3.7)
• 10 Reviews on Jul 21, 2006 (Avg. rating: 3.9)
• 10 Reviews on Jul 23, 2006 (Avg. rating: 3.1)
• 6 Reviews on Jan 9, 2007 (Avg. rating: 3.8)
• 6 Reviews on Jul 24, 2006 (Avg. rating: 3.5)
• 6 Reviews on Dec 31, 2006 (Avg. rating: 3.2)
• 6 Reviews on Jan 18, 2007 (Avg. rating: 2.8)
• 6 Reviews on Dec 27, 2006 (Avg. rating: 2.5)
• 6 Reviews on Dec 20, 2006 (Avg. rating: 2.2)
• 5 Reviews on Dec 21, 2006 (Avg. rating: 4.0)
• 5 Reviews on Jan 29, 2007 (Avg. rating: 3.6)
• 5 Reviews on Feb 27, 2012 (Avg. rating: 3.2)
• 5 Reviews on Jan 1, 2007 (Avg. rating: 3.2)
• 4 Reviews on Jan 14, 2007 (Avg. rating: 4.0)
• 4 Reviews on Dec 28, 2006 (Avg. rating: 3.8)
• 4 Reviews on Dec 29, 2006 (Avg. rating: 3.5)
• 4 Reviews on Dec 26, 2006 (Avg. rating: 3.0)
• 3 Reviews on Feb 19, 2012 (Avg. rating: 4.7)
• 3 Reviews on Jan 27, 2007 (Avg. rating: 4.3)
• 3 Reviews on Mar 8, 2007 (Avg. rating: 4.3)
• 3 Reviews on Jan 3, 2007 (Avg. rating: 3.7)
• 3 Reviews on Aug 10, 2006 (Avg. rating: 3.7)
• 3 Reviews on Jan 22, 2007 (Avg. rating: 3.7)
• 3 Reviews on Jan 23, 2007 (Avg. rating: 3.7)
• 3 Reviews on Jul 27, 2006 (Avg. rating: 3.7)
• 3 Reviews on Dec 23, 2006 (Avg. rating: 3.3)
• 3 Reviews on Dec 19, 2006 (Avg. rating: 3.3)
• 3 Reviews on Aug 3, 2006 (Avg. rating: 3.3)
• 3 Reviews on Feb 5, 2007 (Avg. rating: 3.0)
Show All

In total, we found that 142 reviews were created on just 29 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

Brand Repeaters

• 
• 37%
• Reviewed other products from this brand

241 of the 645 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Read more about our Brand Repeats test.

• 
• 21%
• 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: 21.4% (Avg. rating: 3.3)

In total, we found that 138 reviews (or 21%) 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.

• 
• 8%
• Used substantial repetitive phrases

50 of the 645 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.

• 
• 21%
• Substantial overlapping review history

135 of the 645 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 4.1, while the average ease score for reviewers in this category is 4.3.

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.