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Ecovacs Deebot 901 Robotic Vacuum Cleaner with Smart Navi 3.0
More product info From ECOVACS

Amazon Reviews for  Ecovacs Deebot 901 Robotic Vacuum Cleaner with Smart Navi 3.0
Rating:
601 Ratings
366 Reviews
("Ratings" vs. "Reviews")
5% of potentially unnatural reviews removed (why?)
Adjusted:
View/Edit Adjustment
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Report Info:
Last Updated: Jan 27, 2021
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Note: While Amazon.com claims 601 Ratings, we counted 366 Reviews available on their site.
Note: We only analyze "reviews" and ignore one-tap "ratings".

Report Card

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

Most Trusted Reviews

Ok, wow, here I am giving my first bad review ... [Go to full review]
Apr 9, 2020      
100% TRUST
  • Verified Purchaser
  • Take-Back Reviewer (2 deleted Reviews; avg. rating: 5.0)
  • Easy Grader (avg. rating: 4.5)


Least Trusted Reviews

This robot comes with a very good algorithm to detect ... [Go to full review]
Sep 20, 2018      
19% TRUST
  • Verified Purchaser
  • Overlapping Review History: reviewed 2 of 9 top products
  • Overrepresented Participation (posted 14 Reviews)
  • Easy Grader (avg. rating: 4.6)


Analysis Details

Fail Suspicious Reviewers

Take-Back Reviewers


97 of the 366 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, the discrepancy in ratings between the Take-Back Reviewers and reviewers who don't have any deleted reviews in their history isn't significant enough to rule out the possibility of it being due to random chance.

from take-back reviewers

from reviewers without previously deleted reviews


3.2
3.1


Single-Day Reviewers


5 of the 366 reviewers have written multiple reviews but posted all of them on a single day. The Single-Day reviewers have rated this product an average of 5.0 while all other reviewers rated this product an average of 3.1. 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.

from single-day reviewers

from non-single-day reviewers


5.0
3.1


Read more about our Suspicious Reviewers test.

Fail Overlapping Review History
Reviewers of this product have ALSO reviewed the following products:

Does not include products
from the same brand


41 of the 366 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 3.0. 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


3.9
3.0


Read more about our Overlapping Review History test.

Warn Deleted Reviews

We discovered a total of 11 deleted Reviews for this product, with an average rating of 4.2. 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.

4.2 average rating of deleted reviews

4.2


Show distribution of deleted reviews

Warn Reviewer Participation

  • 69%
  • From reviewers with an overrepresented participation

We see the following 2 participation groups with a statistically significant greater concentration than what we'd expect to see:In total, we found that 254 reviewers (or 69%) are within an overrepresented participation group. This is an excessively high number of reviewers in overrepresented participation groups.

From reviewers with an overrepresented participation

From reviewers with a properly represented participation


3.1
3.1


Read more about our Reviewer Participation test.

Pass Rating Trend

  • 2%
  • Created over 1 day

We counted 366 reviews for this product over the span of 867 days, an average of 0.4 reviews per day. If these reviews were created randomly, there would be a 99.9% chance that we would see 4 or fewer reviews on any given day.

However, we see the following 1 day exceeding this threshold:In total, we found that 7 reviews were created on just 1 day. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

from reviews created on high volume days

from reviews created on normal volume days


3.3
3.1


Read more about our Rating Trend test.

Pass Unverified Purchases

37 of the 366 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.

from unverified purchasers

from verified purchases


3.1
3.1


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

  • 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.

Pass 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:
12 reviews
(3.3/5)
12 reviews
(2.7/5)
9 reviews
(4.2/5)
8 reviews
(3.5/5)
3 reviews
(4.0/5)
5 reviews
(3.4/5)
Show MoreShow Less
Common Phrases in Titles:
8 reviews
(4.1/5)
3 reviews
(1.3/5)


4 of the 366 total reviews for this product use substantial repetitive phrases between them. This is within an acceptable range and it does not appear to be significantly affecting the overall rating for this product.

from reviews with substantial repetitive phrases

from reviews without substantial repetitive phrases


3.5
3.1


Read more about our Phrase Repetition 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 3.8, while the average ease score for reviewers in this category is 4.1.

3.8 Product's Average Ease Score

4.1 Category's Average Ease Score


3.8
4.1


Read more about our Reviewer Ease test.


Pass Brand Repeats

Brand Repeaters


24 of the 366 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.

from Brand Repeaters

from Non-Repeaters


3.0
3.1


Read more about our Brand Repeats test.

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.

  • 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.