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Maximum Willpower: How to master the new science of self-control
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From Kelly McGonigal
This report was last updated 4/1/2017.
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Last Updated: Apr 1, 2017
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Note: We only analyze "reviews" and ignore one-tap "ratings".
Report Card
Pass Overall Grade
FAIL Overlapping Review History
WARN Rating Trend
WARN Suspicious Reviewers
WARN Phrase Repetition
WARN Reviewer Participation
PASS Unverified Purchases
PASS Word Count Comparison
PASS Reviewer Ease
PASS Brand Repeats
PASS Incentivized Reviews
PASS Deleted Reviews
Most Trusted Reviews
This is the same book as Willpower Instinct but apparently ... [Go to full review]
Jan 6, 2013
100%
TRUST
TRUST
- Verified Purchaser
- Critical Reviewer (avg. rating: 2.5)
Least Trusted Reviews
We couldn't find any low-quality reviewsAnalysis Details
Fail Overlapping Review History
Reviewers of this product have ALSO reviewed the following products:
5% also reviewed:
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5% also reviewed:
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5% also reviewed:
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5% also reviewed:
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Does not include products
from the same brand
from the same brand
10 of the 38 reviewers have substantial overlapping product review history. These reviewers have rated this product an average of 3.9 while the reviewers who have a more unique product review history rated this product an average of 4.8. 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 Rating Trend
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- 5%
- Created over 1 day
We counted 38 reviews for this product over the span of 1,799 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, these reviews do not appear to have a significant impact on the overall rating.
Warn Suspicious Reviewers
Take-Back Reviewers
1 of the 38 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.
Warn Phrase Repetition
Reviews that contain one of these phrases are NOT necessarily devalued; read more about how this test works here.
2 of the 38 total reviews for this product use substantial repetitive phrases between them. This is an excessively large percentage which may indicate unnatural reviews.
Warn Reviewer Participation
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- 45%
- 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 17 reviewers (or 45%) are within an overrepresented participation group. While this is more reviews from overrepresented participation groups than we'd expect to see, these reviews do not appear to have a significant impact on the overall rating.
Pass Unverified Purchases
4 of the 38 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 Word Count Comparison
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- 0%
- Have an overrepresented word count
We didn't find any review word count groups that had a statistically significant greater concentration than what we'd expect to see in this category.
Read more about our Word Count Comparison test.
Read more about our Word Count Comparison test.
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 4.3, while the average ease score for reviewers in this category is 4.4.
4.3 Product's Average Ease Score
4.4 Category's Average Ease Score
Read more about our Reviewer Ease test.
Pass Brand Repeats
Brand Repeaters
We didn't detect a substantial amount of Brand Repeaters.
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.
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- 0%
- Admitted to receiving an incentive
We didn't detect any reviews that used language indicating they were incentivized.
Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.
Read more about our Incentivized Reviews test. Check out our study showing that Incentivized Reviewers are much more likely to leave a positive review.
Pass Deleted Reviews
- 0
- Reviews have been deleted
We have not discovered any deleted reviews for this product.
There are a few limitations to keep in mind regarding the Deleted Reviews test:
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.