Rare Earth: Why Complex Life is Uncommon in the Universe
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From Peter D. Ward
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 Astronomy & Space Science with authentic reviews:
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Most Trusted Reviews
TRUST
- Verified Purchaser
- Take-Back Reviewer (2 deleted Reviews; avg. rating: 5.0)
- Easy Grader (avg. rating: 4.6)
Least Trusted Reviews
TRUST
- Unverified Purchaser
- Contains repetitive phrases (show)
- Never-Verified Reviewer
- Take-Back Reviewer (1 deleted Review; avg. rating: 5.0)
- Overrepresented Participation (posted 3 Reviews)
- Critical Reviewer (avg. rating: 4.0)
Analysis Details
122 of the 198 total reviews for this product are unverified purchases. The unverified purchasers have rated this product an average of 3.9 while the verified purchasers have rated this product an average of 4.7. 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.
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.
One-Hit Wonders
22 of the 198 reviewers have only reviewed this product. While this is more One-Hit Wonders than we'd expect to see, it does not appear to have a significant impact on the overall rating.
Never-Verified Reviewers
54 of the 198 reviewers have never written a verified purchase review. While this is more Never-Verified Reviewers than we'd expect to see, it does not appear to have a significant impact on the overall rating.
Take-Back Reviewers
74 of the 198 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 4.1. 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.
We discovered a total of 4 deleted Reviews for this product, with an average rating of 4.3. 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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- 10%
- Created over 8 days
We counted 198 reviews for this product over the span of 7,404 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 8 days exceeding this threshold:In total, we found that 20 reviews were created on just 8 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.
(4.7/5)
(4.2/5)
(4.1/5)
123 of the 198 total reviews for this product use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.
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- 22%
- 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 44 reviews (or 22%) are within an overrepresented word count group. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.
11% also reviewed:
Their Finest Hour (The Second World War) by Churchill, Winston, Sir
10% also reviewed:
Why Evolution Is True by Jerry A. Coyne
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Outrage: The Five Reasons Why O. J. Simpson Got... by Vincent Bugliosi
8% also reviewed:
The Elegant Universe: Superstrings, Hidden... by Brian Greene
7% also reviewed:
Guns, Germs and Steel: The Fate of Human Societies by Jared Diamond
7% also reviewed:
The Hidden Reality: Parallel Universes and the... by Brian Greene
7% also reviewed:
The God Delusion by Richard Dawkins
6% also reviewed:
If the Universe Is Teeming with Aliens ... WHERE... by Stephen Webb
from the same brand
36 of the 198 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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- 25%
- 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 50 reviewers (or 26%) 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.
4.2 Product's Average Ease Score
4.3 Category's Average Ease Score
Read more about our Reviewer Ease test.
Brand Repeaters
6 of the 198 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.
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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.