• 
• 53%
• Created over 29 days

We counted 4,677 reviews for this product over the span of 512 days, an average of 9.1 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 20 or fewer reviews on any given day.

However, we see the following 29 days exceeding this threshold:

• 1086 reviews on Feb 15, 2017 (Avg. rating: 4.4)
• 135 reviews on Jul 18, 2017 (Avg. rating: 4.4)
• 133 reviews on Feb 16, 2017 (Avg. rating: 4.4)
• 122 reviews on Jul 20, 2017 (Avg. rating: 4.4)
• 115 reviews on Feb 13, 2017 (Avg. rating: 4.1)
• 73 reviews on Jul 19, 2017 (Avg. rating: 4.3)
• 70 reviews on Apr 27, 2017 (Avg. rating: 4.4)
• 57 reviews on Apr 26, 2017 (Avg. rating: 4.2)
• 55 reviews on Feb 17, 2017 (Avg. rating: 4.2)
• 54 reviews on Jul 23, 2017 (Avg. rating: 4.7)
• 53 reviews on Jul 24, 2017 (Avg. rating: 4.3)
• 44 reviews on Jul 26, 2017 (Avg. rating: 4.1)
• 43 reviews on Feb 18, 2017 (Avg. rating: 4.2)
• 42 reviews on Feb 19, 2017 (Avg. rating: 4.2)
• 41 reviews on Jul 30, 2017 (Avg. rating: 4.4)
• 37 reviews on Jul 21, 2017 (Avg. rating: 4.4)
• 37 reviews on Jul 14, 2017 (Avg. rating: 3.5)
• 28 reviews on Jul 16, 2017 (Avg. rating: 3.6)
• 26 reviews on Feb 20, 2017 (Avg. rating: 4.4)
• 26 reviews on Jul 13, 2017 (Avg. rating: 4.4)
• 25 reviews on Aug 29, 2017 (Avg. rating: 4.3)
• 25 reviews on Jul 15, 2017 (Avg. rating: 3.9)
• 25 reviews on Feb 14, 2017 (Avg. rating: 3.8)
• 24 reviews on Sep 29, 2017 (Avg. rating: 4.5)
• 24 reviews on Jul 22, 2017 (Avg. rating: 4.3)
• 22 reviews on Jul 12, 2017 (Avg. rating: 3.8)
• 21 reviews on Aug 19, 2017 (Avg. rating: 4.6)
• 21 reviews on Aug 24, 2017 (Avg. rating: 4.4)
• 21 reviews on Jul 25, 2017 (Avg. rating: 4.1)
Show All

In total, we found that 2,485 reviews were created on just 29 days. The reviews on these high volume days have rated this product an average of 4.3 while reviews from other days have rated this product an average of 4.1. 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.

• 
• 5%
• Unverified Purchases

229 of the 4,677 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.4 while the verified purchasers have 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.

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.

One-Hit Wonders

• 
• 26%
• have only posted one review

1,222 of the 4,677 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.

Never-Verified Reviewers

• 
• 2%
• have zero verified purchases

78 of the 4,677 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 3.5 while the reviewers who have written at least one verified purchase review 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.

Take-Back Reviewers

• 
• 4%
• have previously deleted reviews

176 of the 4,677 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

• 
• 2%
• have posted all their reviews on a single day

80 of the 4,677 reviewers have written multiple reviews but posted all of them on a single day. The Single-Day reviewers have rated this product an average of 4.5 while all other reviewers 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.

• 
• 10%
• Used substantial repetitive phrases

468 of the 4,677 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.5 while reviews without substantial repetitive phrases 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 Phrase Repetition test.

• 
• 3%
• Substantial overlapping review history

121 of the 4,677 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.5 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.

• 110
• Reviews have been deleted

We discovered a total of 110 deleted reviews for this product, with an average rating of 4.3. 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 the Deleted Reviews test here.

Show distribution of deleted reviews

Brand Loyalists

• 
• 4%
• Reviewed mostly products from this brand

187 of the 4,677 reviewers have reviewed multiple products but half or more of their reviews are for this brand. While this is more Brand Loyalists than we'd expect to see, the discrepancy in ratings between the Brand Loyalists and non-loyalists isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Brand Repeats test.

• 
• 55%
• 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 1-5 reviews: 54.8% (Avg. rating: 4.2)

In total, we found that 2565 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.

• 
• 0%
• Have an overrepresented word count

We didn't find any review word count groups that had a statistically significant greater concentration than what we'd expect to see in this category.
Read more about our Word Count Comparison 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 4.2, while the average ease score for reviewers in this category is 4.2.

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

We didn't detect any reviews that used language indicating they were incentivized.
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.