Take-Back Reviewers

• 
• 38%
• have previously deleted reviews

336 of the 893 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, it does not appear to have a significant impact on the overall rating.

Single-Day Reviewers

• 
• 0%
• have posted all their reviews on a single day

3 of the 893 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 3.7 while all other reviewers rated this product an average of 4.7. 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.

• 19
• Reviews have been deleted

We discovered a total of 19 deleted Reviews for this product, with an average rating of 4.8. 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

• 
• 57%
• Created over 28 days

We counted 893 reviews for this product over the span of 1,966 days, an average of 0.5 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 4 or fewer reviews on any given day.

However, we see the following 28 days exceeding this threshold:

• 88 Reviews on Jan 11, 2016 (Avg. rating: 4.8)
• 54 Reviews on Jan 12, 2016 (Avg. rating: 4.7)
• 50 Reviews on Jan 23, 2016 (Avg. rating: 4.8)
• 36 Reviews on Jan 13, 2016 (Avg. rating: 4.7)
• 35 Reviews on Jan 16, 2016 (Avg. rating: 4.6)
• 25 Reviews on Jan 15, 2016 (Avg. rating: 4.8)
• 19 Reviews on Jan 18, 2016 (Avg. rating: 4.6)
• 17 Reviews on Jan 24, 2016 (Avg. rating: 4.4)
• 16 Reviews on Jan 19, 2016 (Avg. rating: 4.9)
• 16 Reviews on Jan 17, 2016 (Avg. rating: 4.8)
• 16 Reviews on Jan 14, 2016 (Avg. rating: 4.8)
• 11 Reviews on Jan 20, 2016 (Avg. rating: 4.8)
• 11 Reviews on Feb 2, 2016 (Avg. rating: 4.6)
• 10 Reviews on Jan 21, 2016 (Avg. rating: 4.8)
• 10 Reviews on Jan 25, 2016 (Avg. rating: 4.7)
• 10 Reviews on Jan 26, 2016 (Avg. rating: 4.7)
• 9 Reviews on Jan 22, 2016 (Avg. rating: 5.0)
• 9 Reviews on Feb 9, 2016 (Avg. rating: 4.6)
• 8 Reviews on Jan 27, 2016 (Avg. rating: 4.9)
• 7 Reviews on Feb 16, 2016 (Avg. rating: 4.9)
• 7 Reviews on Feb 6, 2016 (Avg. rating: 4.6)
• 7 Reviews on Feb 3, 2016 (Avg. rating: 4.3)
• 6 Reviews on Jan 31, 2016 (Avg. rating: 5.0)
• 6 Reviews on Jan 28, 2016 (Avg. rating: 4.7)
• 6 Reviews on Jan 30, 2016 (Avg. rating: 4.7)
• 6 Reviews on Feb 1, 2016 (Avg. rating: 4.7)
• 5 Reviews on Jan 29, 2016 (Avg. rating: 4.8)
• 5 Reviews on Mar 15, 2016 (Avg. rating: 3.2)
Show All

In total, we found that 505 reviews were created on just 28 days. This is an excessively high number of reviews submitted on these high volume days.

Read more about our Rating Trend test.

Brand Repeaters

• 
• 43%
• Reviewed other products from this brand

380 of the 893 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, it does not appear to have a significant impact on the overall rating.

Read more about our Brand Repeats test.

• 
• 31%
• Used substantial repetitive phrases

273 of the 893 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.

• 
• 42%
• 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: 10.5% (Avg. rating: 4.7)
• Reviewers with 6-15 Reviews: 17.5% (Avg. rating: 4.7)
• Reviewers with 16-30 Reviews: 14.3% (Avg. rating: 4.7)

In total, we found that 378 reviewers (or 42%) 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.

• 
• 20%
• Unverified Purchases

181 of the 893 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.

• 
• 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.

• 
• 48%
• Substantial overlapping review history

433 of the 893 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 4.5, while the average ease score for reviewers in this category is 4.4. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

On Oct 3, 2016, Amazon prohibited incentivized reviews, however we still test for them since there are still millions in our dataset.

• 
• 3%
• Admitted to receiving an incentive

24 of the 893 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.