• 256
• Reviews have been deleted

We discovered a total of 256 deleted Reviews for this product, with an average rating of 4.6. 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

• 
• 4%
• Created over 12 days

We counted 2,307 reviews for this product over the span of 3,590 days, an average of 0.6 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 5 or fewer reviews on any given day.

However, we see the following 12 days exceeding this threshold:

• 9 Reviews on Dec 24, 2014 (Avg. rating: 4.2)
• 8 Reviews on Jan 7, 2014 (Avg. rating: 4.8)
• 7 Reviews on Dec 28, 2012 (Avg. rating: 4.7)
• 7 Reviews on Jan 8, 2013 (Avg. rating: 4.4)
• 7 Reviews on Feb 24, 2015 (Avg. rating: 4.3)
• 7 Reviews on Jan 3, 2013 (Avg. rating: 4.1)
• 6 Reviews on May 16, 2012 (Avg. rating: 5.0)
• 6 Reviews on Dec 29, 2013 (Avg. rating: 4.8)
• 6 Reviews on Feb 12, 2014 (Avg. rating: 4.3)
• 6 Reviews on Sep 18, 2013 (Avg. rating: 4.0)
• 6 Reviews on Jan 14, 2013 (Avg. rating: 3.3)
• 6 Reviews on Feb 13, 2013 (Avg. rating: 2.8)
Show All

In total, we found that 81 reviews were created on just 12 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 4.0. 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.

• 
• 13%
• Unverified Purchases

311 of the 2,307 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.2 while the verified purchasers have rated this product an average of 4.0. 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.

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

• 
• 1%
• Admitted to receiving an incentive

12 of the 2,307 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 4.7 while reviews that were not incentivized rated this product an average of 4.0. 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.

Never-Verified Reviewers

• 
• 6%
• have zero verified purchases

127 of the 2,307 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 4.3 while the reviewers who have written at least one verified purchase review rated this product an average of 4.0. 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

• 
• 11%
• have previously deleted reviews

261 of the 2,307 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 4.2 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 4.0. 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

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

56 of the 2,307 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 4.3 while all other reviewers rated this product an average of 4.0. 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.

• 
• 2%
• Used substantial repetitive phrases

46 of the 2,307 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.4 while reviews without substantial repetitive phrases rated this product an average of 4.0. 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.

Brand Loyalists

• 
• 3%
• Reviewed mostly products from this brand

68 of the 2,307 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.

• 
• 23%
• 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:

• 26-40 words: 22.7% (Avg. rating: 4.1)

In total, we found that 524 reviews (or 23%) 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.

• 
• 4%
• Substantial overlapping review history

91 of the 2,307 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.

• 
• 0%
• From reviewers with an overrepresented participation

We didn't find any participation groups that had a statistically significant greater concentration than what we'd expect to see in this category.
Read more about our Reviewer Participation 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 4.3.