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

• 
• 2%
• Admitted to receiving an incentive

9 of the 546 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. Incentivized reviews have rated this product an average of 4.1 while reviews that were not incentivized rated this product an average of 4.8. 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.

Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

Never-Verified Reviewers

• 
• 1%
• have zero verified purchases

8 of the 546 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 4.0 while the reviewers who have written at least one verified purchase review rated this product an average of 4.8. 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.

Read more about our Suspicious Reviewers test.

• 
• 75%
• From reviewers with an overrepresented participation

We see the following 3 participation groups with a statistically significant greater concentration than what we'd expect to see:

• Reviewers with 1-5 Reviews: 19.6% (Avg. rating: 4.8)
• Reviewers with 6-15 Reviews: 35.9% (Avg. rating: 4.9)
• Reviewers with 16-30 Reviews: 19.6% (Avg. rating: 4.8)

In total, we found that 410 reviewers (or 75%) are within an overrepresented participation group. These reviews have rated this product an average of 4.9, while all other reviews 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.

Read more about our Reviewer Participation test.

• 7
• Reviews have been deleted

We discovered a total of 7 deleted Reviews for this product, with an average rating of 5. Even though deleted reviews don't affect the average rating, the fact that action was taken to delete reviews raises some red flags about the integrity of the reviews for the product as whole.

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.

Show distribution of deleted reviews

• 
• 17%
• Created over 10 days

We counted 546 reviews for this product over the span of 1,395 days, an average of 0.4 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 4 or fewer reviews on any given day.

However, we see the following 10 days exceeding this threshold:

• 28 Reviews on Jul 15, 2016 (Avg. rating: 4.7)
• 13 Reviews on Jun 14, 2016 (Avg. rating: 4.9)
• 13 Reviews on Jul 16, 2016 (Avg. rating: 4.9)
• 7 Reviews on Aug 23, 2017 (Avg. rating: 4.9)
• 6 Reviews on Aug 10, 2016 (Avg. rating: 4.3)
• 5 Reviews on Jun 11, 2016 (Avg. rating: 5.0)
• 5 Reviews on Jun 27, 2016 (Avg. rating: 5.0)
• 5 Reviews on Jul 23, 2016 (Avg. rating: 5.0)
• 5 Reviews on Aug 16, 2017 (Avg. rating: 5.0)
• 5 Reviews on May 31, 2016 (Avg. rating: 4.8)
Show All

In total, we found that 92 reviews were created on just 10 days. This is an excessively high number of reviews submitted on these high volume days.

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 4.6, while the average ease score for reviewers in this category is 4.4. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

• 
• 55%
• 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: 25.3% (Avg. rating: 4.9)
• 6-15 words: 29.3% (Avg. rating: 4.8)

In total, we found that 298 reviews (or 55%) 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.

• 
• 16%
• Used substantial repetitive phrases

90 of the 546 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.

• 
• 9%
• Unverified Purchases

48 of the 546 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.

• 
• 14%
• Substantial overlapping review history

74 of the 546 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

• 
• 3%
• Reviewed other products from this brand

17 of the 546 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.