A Comparison of Topic Modeling Approaches Using Networked Discussion Forum Posts From the City-data.com Corpus

Ryan M. Omizo

doi:10.5334/johd.182

Figures & Tables

Table 1

City-Data Corpus post count, word count, and date range of postings per forum.

THREAD TOPIC TITLE	LABEL	SAMPLES	DATE RANGE	SUMMARY
How’s everyone doing amongst the Coronavirus shut down? (home, movies) (Advameg, Inc 2020)	coronavirus	481	2020/03/16 – 2020/07/27	Posts discuss experiences with public shutdowns in the opening months of the COVID-19 pandemic in Philadelphia. Content dwells on governmental interventions and the status of public services than the etiology or effects of COVID-19.
“Official Greater Philadelphia Area Crime Thread” (Advameg, Inc, 2013)	crime	2,402	2013/04/11 – 2020/01/15	Posts discuss and share information about crime in Philadelphia.
Official Philadelphia Metro Crime Thread (York, Chester: apartment complexes, houses, unemployment) (Advameg, Inc, 2012a)	crime	1,284	2012/01/12 – 2013/03/11	Posts discuss and share information about crime in the Philadelphia metro area.
Philadelphia 2035 (Houston: foreclosure, neighborhoods, wage) (Advameg, Inc. 2011)	plan	6,796	2011/06/14 – 2020/01/14	Posts discussing Philadelphia’s 2035 civic renovation plan authored by the Philadelphia City Planning Commission (2023).
Retail coming to Philadelphia (Penn, Burlington: real estate, house, buying) (Advameg, Inc. 2012b)	retail	4,045	2012/11/27 – 2020/01/20	Posts discuss new retail business developments in Philadelphia.

Table 2

Tabular data model for City-Data.com forum posts.

POST_ID	POST_BODY	POST	DATETIME	QUOTE_ID	QUOTE_BODY	QUOTE	FORUM
Numerical post identifier	Post HTML	Post text	YYYY-MM-DD HH:MM:SS	Numerical post identifier	Quoted reply HTML	Quoted reply text.	forum title label

Table 3

SE-Topics Coherence and Diversity Scores.

TOPIC MODEL TYPE	UMASS	PUW	JD	WE-CD
SE-Topics post	–4.10	0.74	0.85	0.06
SE-Topics guided topic titles	–2.76	0.54	0.63	0.06
SE-Topics guided initial posts	–2.56	0.52	0.62	0.07
SE-Topics guided high degree	–2.53	0.54	0.63	0.06
SE-Topics threads	–5.46	0.74	0.86	0.12
SE-Topics guided threads topic titles	–4.84	0.69	0.79	0.06
SE-Topics guided threads initial posts	–4.57	0.67	0.78	0.21
SE-Topics guided threads high degree	–4.26	0.67	0.78	0.21
MEAN	–3.88	0.63	0.74	0.11
MAX	–2.53	0.74	0.85	0.21
Q3	–2.66	0.71	0.82	0.17
MEDIAN	–4.18	0.67	0.78	0.07
Q1	–4.70	0.54	0.62	0.06
MIN	–5.46	0.52	0.62	0.06

Table 4

LDA Topic Modeling Coherence and Diversity Scores.

TOPIC MODEL TYPE	UMASS	PUW	JD	WE-CD
LDA posts	–2.59	1.000	0.95	0. 30
guided LDA (topic titles)	–2.63	1.000	0.95	0. 27
guided LDA (high degree)	–2.10	0.950	0.95	0. 29
guided LDA (initial posts)	–2.36	0.975	0.96	0. 26
LDA threads	–2.10	0.950	0.95	0. 30
LDA threads (high degree)	-2.15	0.950	0.95	0. 31
LDA threads (topic titles)	–2.32	0.950	0.95	0. 30
LDA threads (initial post)	–2.22	0.900	0.94	0. 32
MEAN	–2.31	0.95	0.95	0.29
MAX	–2.10	1.00	0.96	0.32
Q3	–2.12	0.98	0.95	0.30
MEDIAN	–2.27	0.95	0.95	0.30
Q1	–2.47	NaN	0.95	0.28
MIN	–2.63	0.9	0.94	0.26

Boxplots of SE-Topics and LDA Coherence Scores.

Boxplots of SE-Topics and LDA Diversity Scores.

Table 5

SE-Topics Guided Post (high degree nodes).

TOPIC	1	2	3	4	5	6	7	8	9	10
0	people	white	crime	black	time	year	murder	think	city	police
1	city	philly	philadelphia	people	street	area	year	think	center	neighborhood
2	building	city	street	project	tower	think	center	market	development	broad
3	store	retail	city	mall	retailer	market	walnut	center	think	location

Table 6

LDA (High Degree) Topic Model.

TOPIC	1	2	3	4	5	6	7	8	9	10
0	money	state	local	people	issue	care	neighborhood	income	help	white
1	store	retail	mall	shopping	retailer	location	center	shop	gallery	also
2	city	think	philadelphia	philly	people	year	time	even	area	much
3	street	market	building	walnut	space	chestnut	center	east	block	south

Table 7

Initial post ids per City-Data.com Corpus forum.

FORUM	POST ID
coronavirus	758124
crime	908813
metro	251839
plan	958364
retail	710692

Table 8

High degree City-Data.com Corpus forum posts used for guided topic modeling.

FORUM	POST ID	DEGREE
coronavirus	57681616	5
crime	50175634	5
metro	22518391	5
plan	38332691	5
retail	38055575	5

Table 9

BERTopic Coherence and Diversity Scores for City-Data.com Corpus.

TOPIC MODEL TYPE	UMASS	PUW	JD	WE-CD
BERTopic posts	–5.12	0.52	0.78	0.12
BERTopic threads	–5.59	0.49	0.79	0. 28

Table 10

BERTopic Post Topic Model. Note that Topic –1 indicates outliers.

TOPIC	0	1	2	3	4	5	6	7	8	9
–1	city	like	people	just	philly	philadelphia	think	dont	street	center
0	city	like	think	new	just	people	building	philadelphia	dont	philly
1	white	people	city	dont	like	crime	im	year	just	murders
2	like	inga	news	just	dont	people	article	think	does	thread
3	bau	hello	nasty	bart	fancy	update	haha	awful	ok	finally

Table 11

BERTopic Thread Level Topic Model. Topic –1 indicates outliers.

0	1	2	3	4	5	6	7	8	9
–1	city	like	people	philly	just	think	dont	philadelphia	new	street
0	city	like	new	store	think	just	philadelphia	retail	stores	people
1	people	crime	city	dont	just	like	white	im	know	year
2	hmmm	hello	fancy	update	haha
3	inga	like	just	news	article	dont	read	writing	people	does