• 
• 23%
• Created over 13 days

We counted 715 reviews for this product over the span of 666 days, an average of 1.1 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 6 or fewer reviews on any given day.

However, we see the following 13 days exceeding this threshold:

• 23 Reviews on Dec 9, 2015 (Avg. rating: 4.7)
• 17 Reviews on Dec 10, 2015 (Avg. rating: 4.6)
• 17 Reviews on Dec 7, 2015 (Avg. rating: 4.5)
• 16 Reviews on Dec 8, 2015 (Avg. rating: 4.8)
• 15 Reviews on Dec 5, 2015 (Avg. rating: 4.8)
• 13 Reviews on Feb 9, 2016 (Avg. rating: 4.0)
• 12 Reviews on Dec 11, 2015 (Avg. rating: 4.7)
• 10 Reviews on Dec 14, 2015 (Avg. rating: 4.6)
• 9 Reviews on Dec 16, 2015 (Avg. rating: 4.6)
• 8 Reviews on Dec 13, 2015 (Avg. rating: 4.8)
• 8 Reviews on Dec 6, 2015 (Avg. rating: 4.3)
• 8 Reviews on Feb 8, 2016 (Avg. rating: 4.3)
• 7 Reviews on Mar 29, 2016 (Avg. rating: 4.1)
Show All

In total, we found that 163 reviews were created on just 13 days. The reviews on these high volume days have rated this product an average of 4.6 while reviews from other days have rated this product an average of 4.2. 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 Rating Trend test.

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

• 
• 20%
• Admitted to receiving an incentive

144 of the 715 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 4.6 while reviews that were not incentivized rated this product an average of 4.2. 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.

One-Hit Wonders

• 
• 11%
• have only posted one review

80 of the 715 reviewers have only reviewed this product. While this is more One-Hit Wonders than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Take-Back Reviewers

• 
• 41%
• have previously deleted reviews

292 of the 715 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 4.5 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 4.2. 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.

• 
• 3%
• Used substantial repetitive phrases

22 of the 715 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.7 while reviews without substantial repetitive phrases rated this product an average of 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.

Read more about our Phrase Repetition test.

• 
• 28%
• Substantial overlapping review history

200 of the 715 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.4 while the reviewers who have a more unique product review history rated this product an average of 4.2. 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 Overlapping Review History test.

• 14
• Reviews have been deleted

We discovered a total of 14 deleted Reviews for this product, with an average rating of 4.9. 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

Brand Repeaters

• 
• 27%
• Reviewed other products from this brand

190 of the 715 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, the discrepancy in ratings between the Brand Repeaters and non-repeaters isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Brand Repeats test.

• 
• 44%
• 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: 23.6% (Avg. rating: 4.2)
• 6-15 words: 20.6% (Avg. rating: 4.4)

In total, we found that 316 reviews (or 44%) 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.

• 
• 51%
• 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: 31.6% (Avg. rating: 4.3)
• Reviewers with 6-15 Reviews: 19.7% (Avg. rating: 4.0)

In total, we found that 367 reviewers (or 51%) 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

68 of the 715 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.

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 4.5.