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VADUUU 枕 安眠枕 人気の肩こり対策 まくら 快眠 高反発枕 いびき防止...
More product info

Brigade Warning!:
Our algorithm has detected a large amount of suspicious negative reviews. Learn more about Review Brigades.
Amazon Reviews for  VADUUU 枕 安眠枕 人気の肩こり対策 まくら 快眠 高反発枕 いびき防止 頚椎サポート 高級ホテル仕様 家族のプレゼント 43x63cm(ホワイト)
Rating:
482 Ratings
297 Reviews
("Ratings" vs. "Reviews")
24% of potentially unnatural reviews removed (why?)
Adjusted:
View/Edit Adjustment
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Report Info:
Last Updated: Aug 8, 2020
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Note: While Amazon.co.jp claims 482 Ratings, we counted 297 Reviews available on their site.
Note: We only analyze "reviews" and ignore one-tap "ratings".

Report Card

Pass Overall Grade
FAIL Deleted Reviews
FAIL Unverified Purchases
FAIL Suspicious Reviewers
WARN Reviewer Ease
WARN Word Count Comparison
WARN Reviewer Participation
PASS Rating Trend
PASS Overlapping Review History
PASS Brand Repeats
N/A Phrase Repetition
N/A Incentivized Reviews

Most Trusted Reviews

睡起來很舒服... [Go to full review]
Apr 23, 2019      
100% TRUST
  • Verified Purchaser
  • Take-Back Reviewer (1 deleted Review; avg. rating: 5.0)
  • Easy Grader (avg. rating: 4.3)


Least Trusted Reviews

4/5
User did not leave written text for this review. [Go to full review]
Dec 30, 2018      
0% TRUST
  • Unverified Purchaser
  • Overrepresented word count (0 words)
  • Never-Verified Reviewer
  • Single-Day Reviewer (posted all reviews on Dec 30, 2018)
  • Overrepresented Participation (posted 2 Reviews)
  • Easy Grader (avg. rating: 4.5)


Analysis Details

Fail Deleted Reviews

We discovered a total of 257 deleted Reviews for this product, with an average rating of 4.9. 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.

4.9 average rating of deleted reviews

4.9


Show distribution of deleted reviews

Fail Unverified Purchases

39 of the 297 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.5 while the verified purchasers 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.

from unverified purchasers

from verified purchases


3.5
4.4


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.

Fail Suspicious Reviewers

Never-Verified Reviewers


16 of the 297 reviewers have never written a verified purchase review. The Never-Verified Reviewers have rated this product an average of 3.1 while the reviewers who have written at least one verified purchase review rated this product an average of 4.3. 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.

from never-verified reviewers

from reviewers with at least one verified purchase review


3.1
4.3


Take-Back Reviewers


51 of the 297 reviewers have had at least one of their past reviews for another product deleted. The Take-Back Reviewers have rated this product an average of 4.5 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 4.2. 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.

from take-back reviewers

from reviewers without previously deleted reviews


4.5
4.2


Read more about our Suspicious Reviewers test.

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

4.3 Product's Average Ease Score

4.2 Category's Average Ease Score


4.3
4.2


Read more about our Reviewer Ease test.


Warn Word Count Comparison
Word counts are approximated for Hanzi and Kanji


  • 96%
  • 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:In total, we found that 284 reviews (or 96%) are within an overrepresented word count group. This is an excessively high number of reviews in overrepresented word count groups.

from reviews with an overrepresented word count

from reviews with a properly represented word count


4.2
4.8


Read more about our Word Count Comparison test.

Warn Reviewer Participation

  • 79%
  • 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:In total, we found that 236 reviewers (or 79%) are within an overrepresented participation group. This is an excessively high number of reviewers in overrepresented participation groups.

From reviewers with an overrepresented participation

From reviewers with a properly represented participation


4.2
4.3


Read more about our Reviewer Participation test.

Pass Rating Trend

  • 0%
  • Created over 2 days
We counted 297 reviews for this product over the span of 821 days, an average of 0.4 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 2 days exceeding this threshold:In total, we found that 0 reviews were created on just 2 days. 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 Rating Trend test.

Pass Overlapping Review History
Reviewers of this product have ALSO reviewed the following products:

5% also reviewed:
... by プリマソーレ(primasole)

4% also reviewed:
... by

Does not include products
from the same brand


47 of the 297 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.

from reviewers with substantial overlapping history

from reviewers without a substantial overlapping history


4.2
4.2


Read more about our Overlapping Review History test.

Pass Brand Repeats

Brand Repeaters


9 of the 297 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.

from Brand Repeaters

from Non-Repeaters


4.3
4.2


Read more about our Brand Repeats test.

N/A Phrase Repetition
We have not yet completed optimization for this test for Hanzi or Kanji.

N/A Incentivized Reviews
We have not yet completed optimization for this test for Hanzi or Kanji.