• 
• 4%
• Unverified Purchases

66 of the 1,719 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.0 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

• 
• 3%
• have only posted one review

49 of the 1,719 reviewers have only reviewed this product. The One-Hit Wonders have rated this product an average of 3.1 while the reviewers who have posted more than one review 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.

Never-Verified Reviewers

• 
• 1%
• have zero verified purchases

19 of the 1,719 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 3.0 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.

Single-Day Reviewers

• 
• 1%
• have posted all their reviews on a single day

20 of the 1,719 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 4.8 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.

• 
• 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: 35.3% (Avg. rating: 4.7)
• 16-25 words: 20.1% (Avg. rating: 4.4)

In total, we found that 952 reviews (or 55%) are within an overrepresented word count group. These reviews have rated this product an average of 4.6, while all other reviews have rated this product an average of 3.8. 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 Word Count Comparison test.

• 
• 4%
• Used substantial repetitive phrases

74 of the 1,719 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 4.2. 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.

• 
• 16%
• Substantial overlapping review history

278 of the 1,719 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.

• 
• 65%
• 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 6-15 Reviews: 41.7% (Avg. rating: 4.3)
• Reviewers with 16-30 Reviews: 23.7% (Avg. rating: 4.3)

In total, we found that 1124 reviewers (or 65%) are within an overrepresented participation group. These reviews have rated this product an average of 4.3, while all other reviews 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 Reviewer Participation test.

• 
• 4%
• Created over 14 days

We counted 1,719 reviews for this product over the span of 3,220 days, an average of 0.5 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 14 days exceeding this threshold:

• 5 Reviews on Sep 14, 2014 (Avg. rating: 5.0)
• 5 Reviews on Nov 28, 2014 (Avg. rating: 5.0)
• 5 Reviews on Jun 18, 2015 (Avg. rating: 5.0)
• 5 Reviews on Sep 19, 2014 (Avg. rating: 4.8)
• 5 Reviews on Dec 17, 2014 (Avg. rating: 4.8)
• 5 Reviews on Aug 17, 2015 (Avg. rating: 4.6)
• 5 Reviews on Mar 22, 2013 (Avg. rating: 4.4)
• 5 Reviews on Jul 3, 2014 (Avg. rating: 4.4)
• 5 Reviews on Sep 20, 2014 (Avg. rating: 4.4)
• 5 Reviews on Jan 28, 2015 (Avg. rating: 4.4)
• 5 Reviews on Dec 27, 2013 (Avg. rating: 4.2)
• 5 Reviews on Sep 15, 2014 (Avg. rating: 3.6)
• 5 Reviews on Aug 3, 2014 (Avg. rating: 3.4)
• 5 Reviews on May 3, 2014 (Avg. rating: 2.0)
Show All

In total, we found that 70 reviews were created on just 14 days. 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 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 4.4, 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.

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

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