• 
• 27%
• Created over 5 days

We counted 167 reviews for this product over the span of 405 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 5 days exceeding this threshold:

• 17 reviews on Apr 13, 2016 (Avg. rating: 5.0)
• 9 reviews on Apr 18, 2016 (Avg. rating: 4.8)
• 9 reviews on Apr 12, 2016 (Avg. rating: 4.6)
• 5 reviews on Apr 14, 2016 (Avg. rating: 5.0)
• 5 reviews on Apr 19, 2016 (Avg. rating: 4.4)

In total, we found that 45 reviews were created on just 5 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

One-Hit Wonders

• 
• 13%
• have only posted one review

22 of the 167 reviewers have only reviewed this product. While this is more One-Hit Wonders than we'd expect to see, the discrepancy in ratings between the One-Hit Wonders and reviewers who have posted more than one review isn't significant enough to rule out the possibility of it being due to random chance.

Take-Back Reviewers

• 
• 5%
• have previously deleted reviews

9 of the 167 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, the discrepancy in ratings between the Take-Back Reviewers and reviewers who don't have any deleted reviews in their history isn't significant enough to rule out the possibility of it being due to random chance.

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 4.5, 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.

• 
• 28%
• Used substantial repetitive phrases

46 of the 167 total reviews for this product use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Phrase Repetition test.

• 
• 88%
• 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: 34.1% (Avg. rating: 4.8)
• Reviewers with 6-15 reviews: 53.9% (Avg. rating: 4.7)

In total, we found that 147 reviewers (or 88%) 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.

• 
• 19%
• Unverified Purchases

32 of the 167 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.

• 
• 19%
• 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: 18.6% (Avg. rating: 4.7)

In total, we found that 31 reviews (or 19%) 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.

• 
• 13%
• Substantial overlapping review history

21 of the 167 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

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.

• 
• 2%
• Admitted to receiving an incentive

4 of the 167 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, or 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 the Deleted Reviews test here.