On Competition, Updated and Expanded Edition
More product info
From Michael E. Porter
Refresh the report to view the most up-to-date data available:
Note: We only analyze "reviews" and ignore one-tap "ratings".
Top products in Economics with authentic reviews:
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Most Trusted Reviews
TRUST
- Verified Purchaser
- Easy Grader (avg. rating: 4.5)
Least Trusted Reviews
TRUST
- Verified Purchaser
- Created on a high volume day
- Brand Loyalist (4 of 5 reviews for this brand; avg rating: 4.8)
- Overlapping Review History: reviewed 1 of 9 top products
- Easy Grader (avg. rating: 4.8)
Analysis Details
We discovered a total of 1 deleted Review for this product, with an average rating of 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:
- 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.
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- 7%
- Created over 1 day
We counted 30 reviews for this product over the span of 4,313 days, an average of 0.0 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 1 or fewer reviews on any given day.
However, we see the following 1 day exceeding this threshold:In total, we found that 2 reviews were created on just 1 day. 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.
Brand Loyalists
1 of the 30 reviewers have reviewed multiple products but half or more of their reviews are for this brand. While this is more Brand Loyalists than we'd expect to see, the discrepancy in ratings between the Brand Loyalists and non-loyalists isn't significant enough to rule out the possibility of it being due to random chance.
Take-Back Reviewers
10 of the 30 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.
4.5 Product's Average Ease Score
4.3 Category's Average Ease Score
Read more about our Reviewer Ease test.
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- 43%
- 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 13 reviewers (or 43%) are within an overrepresented participation group. While this is more reviews from overrepresented participation groups than we'd expect to see, the discrepancy in ratings between reviewers in an overrepresented participation groups and all other reviewers isn’t significant enough to rule out the possibility of it being due to random chance.
9 of the 30 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.
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- 0%
- Have an overrepresented word count
Read more about our Word Count Comparison test.
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- 0%
- Used substantial repetitive phrases
Read more about our Phrase Repetition test.
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7 of the 30 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.
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- 0%
- Admitted to receiving an incentive
Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.