6. Data Used: subreddits & data labeling
Reddit Comments from May 2015
54.5+ million comments with metadata, from 50,138 subreddits
Hateful Subreddits
11 hateful subreddits
565,494 hateful comments:
● 56% body size
● 33.6% gender
● 9.4% race
● 1% religion
Not Hateful Subreddits
13 not hateful subreddits
1,012,052 not hateful comments:
● 75% sometimes controversial
but well-moderated subreddits
● 11.2 % gender
● 7.7 % religion
● 5.4 % body size
● 0.4 % race
7. Tools Used
Computing & Analysis
Natural Language
Processing &
Classification Modeling
NLTK
8. Modeling
TF-IDF on 1.1 million
comments
XGBoost multi-class
classifier
Word2Vec for word
embeddings
9. TF-IDF: Term Frequency-Inverse Document Frequency
words in comments
Image from http://brandonrose.org/clustering
matrix of numbers
i : the word
j: the document
Bag of words + factor to weight rarely occurring words more than common ones
12. Gradient Boosted Trees Classifier
Working on labeled data:
Create one tree & run model
Find residuals (differences between model result & labeled data)
Create 2nd tree to fit to the residuals
New results = results from 1st tree + those from 2nd tree
Find new residuals
Repeat, adding a tree to the model each time to fit the
residuals, until you reach a cut off criteria.
13. ROC Curve: Examine classification model success Most important features
fat
like
peopl
just
white
dont
fuck
im
becaus
game
jew
women
weight
say
14. Potential Use Cases for the Predictive Model
More time for the mods!
User posts hateful comment
Model flags comment as hateful
Comment is in limbo until a
human moderator reads it
Human evaluates comment and
publishes or deletes
Power to the People!
Indicate via user icons or status
information those who have a
recent history of hateful comments.
Let site users decide if they want to
read what this person has to say.
15. Word2Vec: Most Similar Words
“fat”
skinny
ugly
lazy
lard
fatshit
fatass
slenderman
gtbanned
stupid
hamplanet
skinny
overweight
obese
underweight
and
muscular
that
body
is
anorexic
16. Thank You!
Emily Y Spahn
spahn@uw.edu
@eyspahn
https://github.com/eyspahn/OnlineHateSpeech
Clip art in the presentation from https://openclipart.org/