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NATIONAL GEOGRAPHIC Professional Rock Tumbler Kit- Advanced features include Shutoff Timer and...
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From NATIONAL GEOGRAPHIC
This report was last updated 8/19/2020.
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Report Info:
Note: While Amazon.com claims 836 Ratings, we counted 427 Reviews available on their site.
Note: We only analyze "reviews" and ignore one-tap "ratings".
Note: We only analyze "reviews" and ignore one-tap "ratings".
Report Card
Fail Overall Grade
FAIL Suspicious Reviewers
FAIL Word Count Comparison
FAIL Overlapping Review History
WARN Deleted Reviews
WARN Reviewer Participation
PASS Rating Trend
PASS Unverified Purchases
PASS Phrase Repetition
PASS Reviewer Ease
PASS Brand Repeats
PASS Incentivized Reviews
Most Trusted Reviews
Having trouble with the cylinder exploding and grit running out. ... [Go to full review]
Oct 3, 2019
100%
TRUST
TRUST
- Verified Purchaser
- Brand Repeater (2 of 62 reviews for this brand; avg rating: 4.0)
- Easy Grader (avg. rating: 4.9)
Least Trusted Reviews
Won't even turn on!Update: company very good with replacing. [Go to full review]
Dec 30, 2016
0%
TRUST
TRUST
- Unverified Purchaser
- Overrepresented word count (12 words)
- Take-Back Reviewer (1 deleted Review; avg. rating: 1.0)
- Overlapping Review History: reviewed 1 of 9 top products
- Critical Reviewer (avg. rating: 3.2)
Analysis Details
Fail Suspicious Reviewers
Take-Back Reviewers
141 of the 427 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 4.3 while the reviewers who don't have any deleted reviews in their history have rated this product an average of 3.9. 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.
Fail Word Count Comparison
-
- 19%
- 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 82 reviews (or 19%) are within an overrepresented word count group. These reviews have rated this product an average of 4.5, while all other reviews have rated this product an average of 3.9. 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.
Fail Overlapping Review History
Reviewers of this product have ALSO reviewed the following products:
2% also reviewed:
Echo Dot (2nd Generation) - Smart speaker with... by Amazon
2% also reviewed:
AmazonBasics iPad Pro PU Leather Case with Auto... by AmazonBasics
1% also reviewed:
Crystal Allies Materials: 11 Pounds Bulk Rough... by Crystal Allies
1% also reviewed:
Fables, Vol. 18: Cubs in Toyland by Willingham, Bill
1% also reviewed:
Amazon Basic Care Nicotine Polacrilex Uncoated... by Amazon Basic Care
1% also reviewed:
Contigo 2063326 AUTOSEAL West Loop... by Contigo
1% also reviewed:
[Older Version] SanDisk 32GB 2-Pack Ultra... by SanDisk
Does not include products
from the same brand
from the same brand
33 of the 427 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 4.5 while the reviewers who have a more unique product review history rated this product an average of 4.0. 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.
Warn Deleted Reviews
We discovered a total of 10 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:
- 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.
- We have no information on reviews that were never published in the first place.
- 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.
Warn Reviewer Participation
-
- 73%
- 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:In total, we found that 311 reviewers (or 73%) are within an overrepresented participation group. This is an excessively high number of reviewers in overrepresented participation groups.
Pass Rating Trend
-
- 2%
- Created over 2 days
We counted 427 reviews for this product over the span of 1,741 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 2 days exceeding this threshold:In total, we found that 10 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.
Pass Unverified Purchases
27 of the 427 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.
Pass Phrase Repetition
Reviews that contain one of these phrases are NOT necessarily devalued; read more about how this test works here.
Common Phrases in Reviews:
5 reviews
(3.8/5)
(3.8/5)
2 of the 427 total reviews for this product use substantial repetitive phrases between them. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.
Pass 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 4.1, while the average ease score for reviewers in this category is 4.3.
4.1 Product's Average Ease Score
4.3 Category's Average Ease Score
Read more about our Reviewer Ease test.
Pass Brand Repeats
Brand Repeaters
33 of the 427 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.
Pass Incentivized Reviews
On Oct 3, 2016, Amazon prohibited incentivized reviews, however we still test for them since there are still millions in our dataset.
3 of the 427 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.