• 
• 5%
• Unverified Purchases

19 of the 415 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.0 while the verified purchasers have rated this product an average of 4.7. 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.

Take-Back Reviewers

• 
• 30%
• have previously deleted reviews

126 of the 415 reviewers have had at least one of their past reviews for another product deleted. The Take-Back Reviewers have rated this product an average of 4.8 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 4.6. 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.

Read more about our Suspicious Reviewers test.

• 
• 12%
• Created over 15 days

We counted 415 reviews for this product over the span of 4,581 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 15 days exceeding this threshold:

• 4 Reviews on Mar 4, 2016 (Avg. rating: 5.0)
• 4 Reviews on Mar 24, 2016 (Avg. rating: 4.5)
• 4 Reviews on Jan 25, 2016 (Avg. rating: 4.0)
• 3 Reviews on Jul 8, 2015 (Avg. rating: 5.0)
• 3 Reviews on Jan 15, 2016 (Avg. rating: 5.0)
• 3 Reviews on Jan 23, 2016 (Avg. rating: 5.0)
• 3 Reviews on Mar 10, 2016 (Avg. rating: 5.0)
• 3 Reviews on Apr 21, 2016 (Avg. rating: 5.0)
• 3 Reviews on Apr 30, 2017 (Avg. rating: 5.0)
• 3 Reviews on Jan 4, 2016 (Avg. rating: 4.7)
• 3 Reviews on Mar 1, 2016 (Avg. rating: 4.7)
• 3 Reviews on Mar 25, 2016 (Avg. rating: 4.3)
• 3 Reviews on Jun 30, 2016 (Avg. rating: 4.3)
• 3 Reviews on Jan 10, 2016 (Avg. rating: 3.7)
• 3 Reviews on Jul 21, 2016 (Avg. rating: 3.3)
Show All

In total, we found that 48 reviews were created on just 15 days. Although any days with a larger number of reviews than expected is suspicious, these reviews do not appear to have a significant impact on the overall rating.

Read more about our Rating Trend 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. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

• 
• 57%
• 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 2 groups with a statistically significant greater concentration than what we'd expect to see:

• 0-5 words: 27.2% (Avg. rating: 4.8)
• 6-15 words: 29.9% (Avg. rating: 4.6)

In total, we found that 237 reviews (or 57%) are within an overrepresented word count group. This is an excessively high number of reviews in overrepresented word count groups.

Read more about our Word Count Comparison test.

• 
• 0%
• Used substantial repetitive phrases

0 of the 415 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.

• 
• 10%
• Substantial overlapping review history

42 of the 415 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

• 
• 4%
• Reviewed other products from this brand

16 of the 415 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

1 of the 415 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. 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 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.