stackexchange_answers — Stack Exchange question answering (2020)

Description

Bipartite networks of users of question-and-answer sites of the Stack Exchange network and the questions they answered, assembled by A. R. Benson and collaborators from Stack Exchange data. Users and questions are anonymized and given only as integer indices.

mathoverflow: users of MathOverflow (mathoverflow.net, a site for research-level mathematics), each connected to every question they answered. Questions carry the tags assigned to them on the site.
stackoverflow: the same construction for Stack Overflow (stackoverflow.com, a site for programming questions).
algebra, geometry: users of MathOverflow who answered questions whose tags match the patterns "*algebra*" (e.g. lie-algebras, ac.commutative-algebra) or "*geometry*" (e.g. ag.algebraic-geometry, complex-geometry), respectively, obtained from the MathOverflow data dumps. The answers were split into calendar months, and for each month and each matching tag there is a group node connected to all users who answered a question with that tag during that month. The same tag can therefore give rise to many groups (one per month in which it received answers), and identical sets of users can appear in several groups. The answers span the years 2009 to 2019, but the month of each group is not given in the source data. Users who belong to no group were removed.

The source pages do not state when the mathoverflow and stackoverflow data were collected; the data were released in 2020.

The networks have the following properties:

mathoverflow, stackoverflow: is_question, whether the node is a question (otherwise a user); tags, the list of tags of each question (empty for users).
algebra, geometry: is_group, whether the node is a group of users who answered questions with a given tag in a given month (otherwise a user); tag, the question tag of the group (empty for users).

Tags

Social Online Informational Unweighted Metadata

Citation

N. Veldt, A. R. Benson, J. Kleinberg, "Minimizing Localized Ratio Cut Objectives in Hypergraphs." Proceedings of the 26th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining, 1708-1718 (2020) 10.1145/3394486.3403222 Sci-Hub
I. Amburg, N. Veldt, A. R. Benson, "Diverse and Experienced Group Discovery via Hypergraph Clustering." Proceedings of the 2022 SIAM International Conference on Data Mining (SDM), 145-153 (2022) 10.1137/1.9781611977172.17 Sci-Hub

Upstream URL OK

https://www.cs.cornell.edu/~arb/data/mathoverflow-answers/
https://www.cs.cornell.edu/~arb/data/stackoverflow-answers/
https://www.cs.cornell.edu/~arb/data/cat-edge-algebra-questions/
https://www.cs.cornell.edu/~arb/data/cat-edge-geometry-questions/

Upstream license

Creative Commons Attribution-ShareAlike (CC BY-SA; version 3.0 or 4.0, depending on the date of each post), https://stackoverflow.com/help/licensing

Networks

Tip: click on a column header to sort the list, or hover over it for a description.

Column legend

$\left<k\right>$: Mean degree
$\sigma_k$: Standard deviation of the degrees
$\lambda_h$: Largest eigenvalue of the Hashimoto (non-backtracking) matrix
$\tau$: Random walk mixing time
$r$: Degree assortativity
$c$: Global clustering coefficient
$\oslash$: (Pseudo-) diameter
$S$: Relative size of the largest component
NPs: Node properties
EPs: Edge properties

Name	Nodes	Edges	$\left<k\right>$	$\sigma_k$	$\lambda_h$	$\tau$	$r$	$\oslash$	$S$	Kind	Mode	NPs	gt	GraphML	GML	csv
mathoverflow	79,297	131,714	3.32	21.05	25.98	59.54	-0.23	16	1.00	Undirected	Bipartite	is_question tags	622 KiB	968 KiB	955 KiB	1.2 MiB
stackoverflow	16,315,232	26,109,177	3.20	42.36	52.53	396.22	-0.04	26	1.00	Undirected	Bipartite	is_question tags	163.1 MiB	233.5 MiB	219.9 MiB	290.1 MiB
algebra	1,691	8,262	9.77	18.80	27.63	12.44	-0.24	10	1.00	Undirected	Bipartite	is_group tag	13 KiB	27 KiB	27 KiB	28 KiB
geometry	1,773	12,485	14.08	24.94	48.84	7.25	-0.23	8	1.00	Undirected	Bipartite	is_group tag	16 KiB	38 KiB	37 KiB	38 KiB