• 157
• Reviews have been deleted

We discovered a total of 157 deleted reviews for this product, with an average rating of 4.2. 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

Never-Verified Reviewers

• 
• 54%
• have zero verified purchases

248 of the 461 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

• 
• 26%
• have previously deleted reviews

118 of the 461 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.

Read more about our Suspicious Reviewers test.

• 
• 59%
• Created over 16 days

We counted 461 reviews for this product over the span of 1,937 days, an average of 0.2 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 3 or fewer reviews on any given day.

However, we see the following 16 days exceeding this threshold:

• 166 reviews on Apr 18, 2011 (Avg. rating: 4.3)
• 20 reviews on Apr 19, 2011 (Avg. rating: 4.4)
• 13 reviews on Apr 20, 2011 (Avg. rating: 4.2)
• 12 reviews on Apr 17, 2011 (Avg. rating: 4.4)
• 11 reviews on Apr 21, 2011 (Avg. rating: 4.3)
• 6 reviews on Apr 27, 2011 (Avg. rating: 4.2)
• 5 reviews on May 4, 2011 (Avg. rating: 4.6)
• 5 reviews on Apr 23, 2011 (Avg. rating: 4.2)
• 5 reviews on Jun 10, 2011 (Avg. rating: 4.2)
• 4 reviews on Jun 6, 2011 (Avg. rating: 5.0)
• 4 reviews on Jul 21, 2011 (Avg. rating: 5.0)
• 4 reviews on May 3, 2011 (Avg. rating: 4.8)
• 4 reviews on Apr 22, 2011 (Avg. rating: 4.0)
• 4 reviews on May 17, 2011 (Avg. rating: 3.8)
• 4 reviews on Apr 25, 2011 (Avg. rating: 3.0)
• 4 reviews on Aug 31, 2011 (Avg. rating: 3.0)
Show All

In total, we found that 271 reviews were created on just 16 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

• 
• 90%
• Unverified Purchases

413 of the 461 total reviews for this product are unverified purchases. This is an excessively large percentage of unverified purchases and it may indicate 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.

• 
• 11%
• Admitted to receiving an incentive

53 of the 461 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, or check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

• 
• 87%
• Used substantial repetitive phrases

400 of the 461 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.

• 
• 86%
• 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 1-5 reviews: 38.0% (Avg. rating: 4.2)
• Reviewers with 6-15 reviews: 48.2% (Avg. rating: 4.3)

In total, we found that 397 reviewers (or 86%) 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.

• 
• 24%
• 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:

• 101-200 words: 23.9% (Avg. rating: 4.4)

In total, we found that 110 reviews (or 24%) 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.

• 
• 23%
• Substantial overlapping review history

107 of the 461 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 4.3, while the average ease score for reviewers in this category is 4.4.

Brand Repeaters

• 
• 6%
• Reviewed other products from this brand

28 of the 461 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.