• 499
• Reviews have been deleted

We discovered a total of 499 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 our Deleted Reviews test.

Show distribution of deleted reviews

• 
• 8%
• Created over 17 days

We counted 1,800 reviews for this product over the span of 1,122 days, an average of 1.6 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 7 or fewer reviews on any given day.

However, we see the following 17 days exceeding this threshold:

• 12 Reviews on Sep 15, 2016 (Avg. rating: 4.4)
• 10 Reviews on Jun 21, 2016 (Avg. rating: 4.5)
• 10 Reviews on Mar 29, 2016 (Avg. rating: 4.4)
• 10 Reviews on Jul 25, 2016 (Avg. rating: 4.3)
• 9 Reviews on Aug 23, 2016 (Avg. rating: 4.8)
• 9 Reviews on May 31, 2016 (Avg. rating: 4.4)
• 9 Reviews on Aug 13, 2016 (Avg. rating: 4.4)
• 9 Reviews on Jun 27, 2016 (Avg. rating: 4.1)
• 9 Reviews on Aug 20, 2016 (Avg. rating: 3.7)
• 8 Reviews on Sep 7, 2016 (Avg. rating: 4.5)
• 8 Reviews on Jul 6, 2016 (Avg. rating: 4.4)
• 8 Reviews on Aug 15, 2016 (Avg. rating: 4.1)
• 8 Reviews on Sep 6, 2016 (Avg. rating: 4.1)
• 8 Reviews on Feb 18, 2016 (Avg. rating: 4.0)
• 8 Reviews on Jul 14, 2016 (Avg. rating: 3.5)
• 8 Reviews on Mar 15, 2016 (Avg. rating: 3.4)
• 8 Reviews on Mar 17, 2016 (Avg. rating: 3.4)
Show All

In total, we found that 151 reviews were created on just 17 days. The reviews on these high volume days have rated this product an average of 4.2 while reviews from other days have rated this product an average of 3.9. 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.

• 
• 14%
• Unverified Purchases

245 of the 1,800 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.3 while the verified purchasers 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.

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

• 
• 20%
• have only posted one review

357 of the 1,800 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

36 of the 1,800 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 3.2 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

• 
• 21%
• have previously deleted reviews

383 of the 1,800 reviewers have had at least one of their past reviews for another product deleted. This is an excessively large percentage of Take-Back Reviewers which may indicate unnatural reviews.

Single-Day Reviewers

• 
• 5%
• have posted all their reviews on a single day

98 of the 1,800 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 3.9. 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.

• 
• 21%
• Substantial overlapping review history

372 of the 1,800 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 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 Overlapping Review History test.

• 
• 39%
• 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: 39.4% (Avg. rating: 3.8)

In total, we found that 709 reviewers (or 39%) are within an overrepresented participation group. While this is more reviews from overrepresented participation 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 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.

• 
• 3%
• Used substantial repetitive phrases

51 of the 1,800 total reviews for this product use substantial repetitive phrases between them. 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 Phrase Repetition 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 4.1, while the average ease score for reviewers in this category is 4.3.

Brand Repeaters

• 
• 9%
• Reviewed other products from this brand

160 of the 1,800 reviewers have reviewed other products for this brand. 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 Brand Repeats test.

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

1 of the 1,800 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. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.