Never-Verified Reviewers

• 
• 81%
• have zero verified purchases

7,400 of the 9,192 reviewers have never written a verified purchase review. This is an excessively large percentage of Never-Verified Reviewers which may indicate unnatural reviews.

Take-Back Reviewers

• 
• 1%
• have previously deleted reviews

104 of the 9,192 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.

Single-Day Reviewers

• 
• 64%
• have posted all their reviews on a single day

5,925 of the 9,192 reviewers have written multiple reviews but posted all of them on a single day. This is an excessively large percentage of Single-Day Reviewers which may indicate unnatural reviews.

Read more about our Suspicious Reviewers 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 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.

• 
• 77%
• Created over 1 day

We counted 9,192 reviews for this product over the span of 4 days, an average of 2,298.0 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 2420 or fewer reviews on any given day.

However, we see the following 1 day exceeding this threshold:

• 7061 Reviews on Mar 7, 2019 (Avg. rating: 5.0)

In total, we found that 7,061 reviews were created on just 1 day. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 100%
• Unverified Purchases

9,192 of the 9,192 total reviews for this product are unverified purchases. This is an excessively large percentage of unverified purchases and it may indicate 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.

• 
• 76%
• 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:

• 41-65 words: 49.2% (Avg. rating: 5.0)
• 66-100 words: 26.6% (Avg. rating: 5.0)

In total, we found that 6,964 reviews (or 76%) 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.

• 
• 21%
• Used substantial repetitive phrases

1,898 of the 9,192 total reviews for this product use substantial repetitive phrases between them. While this is more than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Read more about our Phrase Repetition test.

• 
• 88%
• Substantial overlapping review history

8,118 of the 9,192 reviewers have substantial overlapping product review history. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Overlapping Review History test.

• 
• 62%
• From reviewers with an overrepresented participation

We see the following 1 participation group with a statistically significant greater concentration than what we'd expect to see:

• Reviewers with 31-50 Reviews: 61.5% (Avg. rating: 5.0)

In total, we found that 5655 reviewers (or 62%) 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.

Brand Repeaters

We didn't detect a substantial amount of Brand Repeaters.

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

18 of the 9,192 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.