A Guide to the Project Management Body of Knowledge (PMBOK Guide)Fifth Edition
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From Project Management Institute
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 Leadership & Motivation with authentic reviews:
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Most Trusted Reviews
TRUST
- Verified Purchaser
- Take-Back Reviewer (2 deleted Reviews; avg. rating: 4.0)
- Brand Repeater (2 of 40 reviews for this brand; avg rating: 2.5)
- Overlapping Review History: reviewed 1 of 9 top products
- Critical Reviewer (avg. rating: 3.9)
Least Trusted Reviews
TRUST
- Unverified Purchaser
- Created on a high volume day
- Overrepresented word count (12 words)
- Contains repetitive phrases (show)
- One-Hit Wonder
- Never-Verified Reviewer
- Overrepresented Participation (posted 1 Review)
- Easy Grader (avg. rating: 5.0)
Analysis Details
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- 75%
- 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 4 groups with a statistically significant greater concentration than what we'd expect to see:In total, we found that 1,299 reviews (or 75%) are within an overrepresented word count group. These reviews have rated this product an average of 4.4, while all other reviews have rated this product an average of 3.6. 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.
96 of the 1,735 total reviews for this product use substantial repetitive phrases between them. These reviewers have rated this product an average of 4.5 while reviews without substantial repetitive phrases 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.
We discovered a total of 30 deleted Reviews for this product, with an average rating of 4.4. 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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- 6%
- Created over 26 days
We counted 1,735 reviews for this product over the span of 6,799 days, an average of 0.3 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 26 days exceeding this threshold:In total, we found that 108 reviews were created on just 26 days. 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.
One-Hit Wonders
227 of the 1,735 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.
Take-Back Reviewers
442 of the 1,735 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.
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- 78%
- 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 1353 reviewers (or 78%) are within an overrepresented participation group. This is an excessively high number of reviewers in overrepresented participation groups.
212 of the 1,735 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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170 of the 1,735 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.
4.3 Product's Average Ease Score
4.4 Category's Average Ease Score
Read more about our Reviewer Ease test.
Brand Repeaters
32 of the 1,735 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.