• 408
• Reviews have been deleted

We discovered a total of 408 deleted Reviews for this product, with an average rating of 4.4. 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

• 
• 67%
• 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: 29.8% (Avg. rating: 4.7)
• Reviewers with 6-15 Reviews: 36.8% (Avg. rating: 4.6)

In total, we found that 190 reviewers (or 67%) are within an overrepresented participation group. These reviews have rated this product an average of 4.6, while all other reviews have rated this product an average of 4.4. 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 Reviewer Participation test.

• 
• 12%
• Created over 9 days

We counted 285 reviews for this product over the span of 2,010 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 9 days exceeding this threshold:

• 5 Reviews on Dec 1, 2015 (Avg. rating: 5.0)
• 5 Reviews on Feb 10, 2016 (Avg. rating: 4.6)
• 4 Reviews on Nov 25, 2016 (Avg. rating: 5.0)
• 4 Reviews on Feb 24, 2016 (Avg. rating: 4.5)
• 3 Reviews on Feb 9, 2016 (Avg. rating: 5.0)
• 3 Reviews on Oct 13, 2015 (Avg. rating: 4.3)
• 3 Reviews on Nov 22, 2015 (Avg. rating: 4.3)
• 3 Reviews on Mar 26, 2016 (Avg. rating: 4.3)
• 3 Reviews on Feb 26, 2016 (Avg. rating: 4.0)
Show All

In total, we found that 33 reviews were created on just 9 days. Although any days with a larger number of reviews than expected is suspicious, these reviews do not appear to have a significant impact on the overall rating.

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 4.4. While this discrepancy is rather large, it is not quite large enough to rule out the possibility of it being due random chance.

• 
• 6%
• Used substantial repetitive phrases

16 of the 285 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.

• 
• 12%
• Unverified Purchases

34 of the 285 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.

One-Hit Wonders

• 
• 7%
• have only posted one review

20 of the 285 reviewers have only reviewed this product. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

Never-Verified Reviewers

• 
• 1%
• have zero verified purchases

4 of the 285 reviewers have never written a verified purchase review. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

Take-Back Reviewers

• 
• 21%
• have previously deleted reviews

59 of the 285 reviewers have had at least one of their past reviews for another product deleted. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

Single-Day Reviewers

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

1 of the 285 reviewers have written multiple reviews but posted all of them on a single day. 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 Suspicious Reviewers test.

• 
• 6%
• Substantial overlapping review history

17 of the 285 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

We didn't detect a substantial amount of Brand Repeaters.

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

• 
• 1%
• Admitted to receiving an incentive

3 of the 285 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.