• 
• 12%
• Created over 20 days

We counted 767 reviews for this product over the span of 3,116 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 20 days exceeding this threshold:

• 8 Reviews on Sep 16, 2008 (Avg. rating: 2.8)
• 6 Reviews on Sep 19, 2008 (Avg. rating: 3.8)
• 6 Reviews on Nov 2, 2008 (Avg. rating: 3.5)
• 6 Reviews on Aug 27, 2008 (Avg. rating: 3.0)
• 6 Reviews on Sep 30, 2008 (Avg. rating: 2.7)
• 5 Reviews on Dec 1, 2008 (Avg. rating: 4.4)
• 4 Reviews on Jan 7, 2009 (Avg. rating: 4.3)
• 4 Reviews on Nov 29, 2008 (Avg. rating: 4.0)
• 4 Reviews on Jul 23, 2008 (Avg. rating: 3.8)
• 4 Reviews on Jan 13, 2009 (Avg. rating: 3.8)
• 4 Reviews on Aug 9, 2008 (Avg. rating: 3.5)
• 4 Reviews on Aug 12, 2008 (Avg. rating: 3.5)
• 4 Reviews on Nov 23, 2008 (Avg. rating: 3.5)
• 4 Reviews on Dec 12, 2008 (Avg. rating: 3.5)
• 4 Reviews on Jan 11, 2009 (Avg. rating: 3.5)
• 4 Reviews on Oct 15, 2008 (Avg. rating: 3.3)
• 4 Reviews on Jul 11, 2008 (Avg. rating: 3.0)
• 4 Reviews on Sep 15, 2008 (Avg. rating: 3.0)
• 4 Reviews on Sep 8, 2008 (Avg. rating: 2.5)
• 4 Reviews on Sep 24, 2008 (Avg. rating: 2.5)
Show All

In total, we found that 93 reviews were created on just 20 days. The reviews on these high volume days have rated this product an average of 3.4 while reviews from other days have rated this product an average of 2.9. 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.

One-Hit Wonders

• 
• 20%
• have only posted one review

157 of the 767 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

• 
• 24%
• have zero verified purchases

184 of the 767 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

• 
• 23%
• have previously deleted reviews

174 of the 767 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

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

12 of the 767 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 3.8 while all other reviewers rated this product an average of 3.0. 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.

• 
• 8%
• Used substantial repetitive phrases

58 of the 767 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 3.5 while reviews without substantial repetitive phrases rated this product an average of 2.9. 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 Phrase Repetition test.

• 
• 52%
• Unverified Purchases

399 of the 767 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.

• 
• 52%
• 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: 52.2% (Avg. rating: 3.0)

In total, we found that 400 reviewers (or 52%) 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.

• 
• 26%
• 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: 26.1% (Avg. rating: 2.8)

In total, we found that 200 reviews (or 26%) 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.

• 
• 2%
• Substantial overlapping review history

13 of the 767 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 3.6, while the average ease score for reviewers in this category is 4.3.

Brand Repeaters

• 
• 2%
• Reviewed other products from this brand

19 of the 767 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.

• 0
• Reviews have been deleted

We have not discovered any deleted reviews for this product.

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.