• 1
• Review has been deleted

We discovered a total of 1 deleted Review for this product, with an average rating of 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

• 
• 16%
• Created over 12 days

We counted 264 reviews for this product over the span of 2,213 days, an average of 0.1 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 2 or fewer reviews on any given day.

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

• 4 Reviews on Sep 6, 2011 (Avg. rating: 4.8)
• 4 Reviews on Mar 29, 2016 (Avg. rating: 4.8)
• 4 Reviews on Aug 4, 2011 (Avg. rating: 4.3)
• 4 Reviews on Sep 13, 2011 (Avg. rating: 4.3)
• 4 Reviews on Aug 25, 2011 (Avg. rating: 4.0)
• 3 Reviews on Aug 10, 2011 (Avg. rating: 5.0)
• 3 Reviews on Aug 15, 2011 (Avg. rating: 5.0)
• 3 Reviews on Sep 12, 2011 (Avg. rating: 4.7)
• 3 Reviews on Oct 5, 2011 (Avg. rating: 4.7)
• 3 Reviews on Aug 5, 2011 (Avg. rating: 4.0)
• 3 Reviews on Aug 31, 2011 (Avg. rating: 3.3)
• 3 Reviews on Sep 19, 2011 (Avg. rating: 3.3)
Show All

In total, we found that 41 reviews were created on just 12 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 59%
• Unverified Purchases

157 of the 264 total reviews for this product are unverified purchases. While this is a higher percentage of unverified purchases than we'd expect to see, it does not appear to have a significant impact on the overall rating.

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.

• 
• 7%
• Admitted to receiving an incentive

19 of the 264 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. This is more than we would expect see; the presences of at least one incentivized review indicates that there may be more, since not all reviewers will disclose that they had received an incentive to post a review.

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

• 
• 22%
• have zero verified purchases

57 of the 264 reviewers have never written a verified purchase review. While this is more Never-Verified Reviewers than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Take-Back Reviewers

• 
• 6%
• have previously deleted reviews

17 of the 264 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, the discrepancy in ratings between the Take-Back Reviewers and reviewers who don't have any deleted reviews in their history isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Suspicious Reviewers test.

• 
• 59%
• Used substantial repetitive phrases

157 of the 264 total reviews for this product use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.

Read more about our Phrase Repetition test.

• 
• 83%
• From reviewers with an overrepresented participation

We see the following 3 participation groups with a statistically significant greater concentration than what we'd expect to see:

• Reviewers with 1-5 Reviews: 39.8% (Avg. rating: 4.4)
• Reviewers with 6-15 Reviews: 28.0% (Avg. rating: 4.5)
• Reviewers with 16-30 Reviews: 14.8% (Avg. rating: 4.5)

In total, we found that 218 reviewers (or 83%) 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.

• 
• 27%
• Substantial overlapping review history

72 of the 264 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.

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 4.4.

Brand Repeaters

• 
• 1%
• Reviewed other products from this brand

2 of the 264 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.