One-Hit Wonders

• 
• 14%
• have only posted one review

66 of the 480 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.

Take-Back Reviewers

• 
• 13%
• have previously deleted reviews

62 of the 480 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.

• 12
• Reviews have been deleted

We discovered a total of 12 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

• 
• 15%
• Created over 13 days

We counted 480 reviews for this product over the span of 3,181 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 13 days exceeding this threshold:

• 9 Reviews on Jul 1, 2010 (Avg. rating: 4.9)
• 7 Reviews on Jul 28, 2010 (Avg. rating: 5.0)
• 7 Reviews on Aug 1, 2010 (Avg. rating: 5.0)
• 6 Reviews on Aug 21, 2010 (Avg. rating: 5.0)
• 6 Reviews on Jul 2, 2010 (Avg. rating: 4.7)
• 6 Reviews on Jul 11, 2010 (Avg. rating: 4.7)
• 6 Reviews on Jul 31, 2010 (Avg. rating: 4.7)
• 5 Reviews on Jul 26, 2010 (Avg. rating: 5.0)
• 4 Reviews on Jul 5, 2010 (Avg. rating: 5.0)
• 4 Reviews on Jul 15, 2010 (Avg. rating: 5.0)
• 4 Reviews on Aug 3, 2010 (Avg. rating: 5.0)
• 4 Reviews on Aug 6, 2010 (Avg. rating: 5.0)
• 4 Reviews on Jul 8, 2010 (Avg. rating: 4.8)
Show All

In total, we found that 72 reviews were created on just 13 days. This is an excessively high number of reviews submitted on these high volume days.

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 4.5, 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.

• 
• 18%
• Used substantial repetitive phrases

87 of the 480 total reviews for this product use substantial repetitive phrases between them. While this is more than we'd expect to see, the discrepancy in ratings between the these reviews and reviews without substantial repetitive phrases isn't significant enough to rule out the possibility of it being due to random chance.

Read more about our Phrase Repetition test.

• 
• 35%
• 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: 35.0% (Avg. rating: 4.9)

In total, we found that 168 reviewers (or 35%) 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.

• 
• 24%
• Unverified Purchases

114 of the 480 total reviews for this product are unverified purchases. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

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.

• 
• 14%
• 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: 13.8% (Avg. rating: 5.0)

In total, we found that 66 reviews (or 14%) 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.

• 
• 16%
• Substantial overlapping review history

77 of the 480 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.

Brand Repeaters

• 
• 3%
• Reviewed other products from this brand

15 of the 480 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

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.