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 4.5, while the average ease score for reviewers in this category is 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.

• 
• 8%
• Created over 9 days

We counted 351 reviews for this product over the span of 6,951 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 9 days exceeding this threshold:

• 5 Reviews on Feb 6, 2017 (Avg. rating: 5.0)
• 3 Reviews on Apr 21, 2016 (Avg. rating: 5.0)
• 3 Reviews on Jul 3, 2016 (Avg. rating: 5.0)
• 3 Reviews on Nov 11, 2016 (Avg. rating: 5.0)
• 3 Reviews on Jan 5, 2017 (Avg. rating: 5.0)
• 3 Reviews on Jan 15, 2017 (Avg. rating: 5.0)
• 3 Reviews on Feb 2, 2017 (Avg. rating: 5.0)
• 3 Reviews on Feb 4, 2017 (Avg. rating: 5.0)
• 3 Reviews on Feb 24, 2017 (Avg. rating: 5.0)
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In total, we found that 29 reviews were created on just 9 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.

Take-Back Reviewers

• 
• 29%
• have previously deleted reviews

102 of the 351 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.

• 
• 35%
• 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:

• 6-15 words: 35.3% (Avg. rating: 5.0)

In total, we found that 124 reviews (or 35%) are within an overrepresented word count group. While this is more reviews from overrepresented word count groups than we'd expect to see, these reviews do not appear to have a significant impact on the overall rating.

Read more about our Word Count Comparison test.

• 
• 55%
• 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: 22.8% (Avg. rating: 4.9)
• Reviewers with 6-15 Reviews: 32.5% (Avg. rating: 5.0)

In total, we found that 194 reviewers (or 55%) 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.

• 
• 10%
• Unverified Purchases

36 of the 351 total reviews for this product are unverified purchases. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

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.

• 
• 0%
• Used substantial repetitive phrases

0 of the 351 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.

• 
• 6%
• Substantial overlapping review history

21 of the 351 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.

Brand Repeaters

• 
• 1%
• Reviewed other products from this brand

4 of the 351 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.

• 
• 1%
• Admitted to receiving an incentive

2 of the 351 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.