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BRI Nutrition L-Tryptophan - 1500mg Servings - 60 Count of L Tryptophan - 500 mg per Veggie Capsules
More product info From BRI Nutrition

Amazon Reviews for  BRI Nutrition L-Tryptophan - 1500mg Servings - 60 Count of L Tryptophan - 500 mg per Veggie Capsules
Rating:
333 Ratings
100 Reviews
("Ratings" vs. "Reviews")
66% of potentially unnatural reviews removed (why?)
Adjusted:
View/Edit Adjustment
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Report Info:
Last Updated: Nov 16, 2018
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Show Report History
Note: While Amazon.com claims 333 Ratings, we counted 100 Reviews available on their site.
Note: We only analyze "reviews" and ignore one-tap "ratings".

Report Card

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

Most Trusted Reviews

1/5
Doesn't work. Consult a doctor if your taking other meds ... [Go to full review]
Oct 14, 2016      
100% TRUST
  • Verified Purchaser
  • Take-Back Reviewer (5 deleted Reviews; avg. rating: 4.8)
  • Overrepresented Participation (posted 95 Reviews)
  • Critical Reviewer (avg. rating: 3.8)


Least Trusted Reviews

I've recently had trouble with sleeping due to very erratic ... [Go to full review]
Aug 31, 2015     1 of 1 found this helpful.  
0% TRUST
  • Unverified Purchaser
  • Overrepresented word count (156 words)
  • Take-Back Reviewer (2 deleted Reviews; avg. rating: 5.0)
  • Brand Loyalist (15 of 21 reviews for this brand; avg rating: 5.0)
  • Overlapping Review History: reviewed 3 of 9 top products
  • Easy Grader (avg. rating: 5.0)


Analysis Details

Fail Deleted Reviews

We discovered a total of 164 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.

4.8 average rating of deleted reviews

4.8


Show distribution of deleted reviews

Fail Unverified Purchases

49 of the 100 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 4.8 while the verified purchasers 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 unverified purchasers

from verified purchases


4.8
4.2


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 Brand Repeats

Brand Repeaters


50 of the 100 reviewers have reviewed other products for this brand. While this is more Brand Repeaters than we'd expect to see, the discrepancy in ratings between the Brand Repeaters and non-repeaters isn't significant enough to rule out the possibility of it being due to random chance.

from Brand Repeaters

from Non-Repeaters


4.7
4.3


Brand Loyalists


6 of the 100 reviewers have reviewed multiple products but half or more of their reviews are for this brand. This is an excessively large percentage of Brand Loyalists which may indicate unnatural reviews.

from Brand Loyalists

from Non-Loyalists


5.0
4.5


Read more about our Brand Repeats test.

Fail Suspicious Reviewers

Take-Back Reviewers


60 of the 100 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.

from take-back reviewers

from reviewers without previously deleted reviews


4.6
4.4


Read more about our Suspicious Reviewers test.

Fail 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 4.5, while the average ease score for reviewers in this category is 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.

4.5 Product's Average Ease Score

4.3 Category's Average Ease Score


4.5
4.3


Read more about our Reviewer Ease test.


Fail Overlapping Review History
Does not include products
from the same brand


32 of the 100 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 5.0 while the reviewers who have a more unique product review history 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 reviewers with substantial overlapping history

from reviewers without a substantial overlapping history


5.0
4.3


Read more about our Overlapping Review History test.

Warn Rating Trend

  • 6%
  • Created over 2 days

We counted 100 reviews for this product over the span of 742 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 2 days exceeding this threshold:In total, we found that 6 reviews were created on just 2 days. Although any days with a larger number of reviews than expected is suspicious, the discrepancy in ratings from reviews created on these high volume days and reviews created on other days isn't significant enough to rule out the possibility of it being due to random chance.

from reviews created on high volume days

from reviews created on normal volume days


5.0
4.5


Read more about our Rating Trend test.

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


10 of the 100 total reviews for this product admitted to receiving a free or discounted product in exchange for a review. While we could not find a statistically significant difference between the average rating of incentivized reviews and non-incentivized reviews, the presences of at least one incentivized review indicates that there may be more, since not all reviewers will disclose that they had received an incentive to post a review.

from incentivized reviews

from non-incentivized reviews


4.7
4.5


Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.

Warn Word Count Comparison

  • 41%
  • 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 2 groups with a statistically significant greater concentration than what we'd expect to see:In total, we found that 41 reviews (or 41%) are within an overrepresented word count group. While this is more reviews from overrepresented word count groups than we'd expect to see, the discrepancy in ratings between reviews with overrepresented word groups and all other reviews isn’t significant enough to rule out the possibility of it being due to random chance.

from reviews with an overrepresented word count

from reviews with a properly represented word count


4.6
4.4


Read more about our Word Count Comparison test.

Warn 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:
4 reviews
(4.3/5)
3 reviews
(5.0/5)
3 reviews
(5.0/5)
4 reviews
(5.0/5)
2 reviews
(4.0/5)
4 reviews
(5.0/5)
2 reviews
(5.0/5)
2 reviews
(5.0/5)
Show MoreShow Less
Common Phrases in Titles:
2 reviews
(3.5/5)
3 reviews
(5.0/5)
2 reviews
(5.0/5)


28 of the 100 total reviews for this product use substantial repetitive phrases between them. While this is more than we'd expect to see, the discrepancy in ratings between the these reviews and reviews without substantial repetitive phrases isn't significant enough to rule out the possibility of it being due to random chance.

from reviews with substantial repetitive phrases

from reviews without substantial repetitive phrases


4.7
4.4


Read more about our Phrase Repetition test.

Pass Reviewer Participation

  • 22%
  • 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:In total, we found that 22 reviewers (or 22%) are within an overrepresented participation group. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

From reviewers with an overrepresented participation

From reviewers with a properly represented participation


4.2
4.6


Read more about our Reviewer Participation test.