Political Discourse on Social Media: Echo Chambers, Gatekeepers, and the Price of Bipartisanship

Kiran Garimella, Gianmarco De Francisci Morales, Aristides Gionis, Michael Mathioudakis · The Web Conference (WWW) · 2018 · political-science · record garimella2018-political-discourse
tag layer · index · concepts · authors · עברית

Where this record's text came from. faceted 2026-08 by reading the locally held text (pdftext); every evidence string verified as an exact substring of that text before merging. method is not on the suggested list: this is large-scale observational analysis of retrospective Twitter data plus a Random Forest prediction task, so I used 'observational-data-analysis' rather than forcing 'behavioural-experiment' (no manipulation) or 'system-or-tool-building'. Claim type is 'existence' for the headline echo-chamber finding; the paper also contributes measures (method-shaped) and a price-of-bipartisanship association, but its own Discussion frames the primary result as supporting existence. The 'extends' relation names no single prior author in the evidence sentence, but the surrounding paragraph explicitly enumerates the content-only [4, 21, 26] and network-only [1, 2] studies being extended. 2026-08-14, 2026-08-15 and 2026-08-16 schema-0.3 passes: every quote verified as an exact substring of the staged text and anchored at merge time; concept terms verified present; every edge endpoint an existing node.

1 quote on this page may have lost a superscript, a subscript or a fraction slash. Nothing in it is corrupt — every character survived. What did not survive is POSITION: whether a digit sat above the line, below it, or between two others. So x 10 9 may be x 10⁹, chi 2 5 may be chi-squared with five degrees of freedom, and 1 2 may be one half. Read any expression here against the published paper before relying on it.

How to read this page. The article itself is not reproduced here — this paper is not cleared for redistribution, so what follows is the tag layer alone. The evidence sentences are withheld with the article. The table at the foot lists every tag the record carries; each row names the facet it belongs to, and the whose words column says whether the tag records the paper's own wording or the tagger's sentence about the paper. Every tag links to each other paper in the corpus carrying it. The machine-readable edition of the same thing is the TEI file beside this one, where the tags live in standOff, and the article is at its publisher via the link below. When we have changed our mind. Some entries in the table begin with a word in capitals and the reason for it. EVIDENCE CORRECTED — the finding still stands, but we had quoted the wrong sentence from the paper, and the quotation has been replaced with the right one. RETRACTED — the entry itself was wrong; it stays on the page, marked, with the reason, rather than being deleted. WITHDRAWN AND REPLACED — the entry was wrong, and a corrected version of it appears in the entries below. Each mark carries its own reason, in brackets, because the reasons differ from one entry to the next. An entry we have WITHDRAWN is removed from this page and kept in the record, with its reason. A line reading Audit and a date is a later re-reading of the entry against its whole sentence: DOUBTFUL means it was kept, and the reason says what is loose about it. Quotation marks inside the tagger's sentence. Where a tag is the tagger's own sentence, a phrase in quotation marks inside it is borrowed from the paper — the tagger's wording around it is not. The paper's own sentence is the evidence quote for that row; on this page it is withheld with the article, and the article is at its publisher. Nothing inside quotation marks anywhere on this page is ours: if it is quoted, it is the paper's. Whose words a concept carries. A concept entry records a term the paper itself uses, so the term, the sense given for it, and its evidence are the paper's own words, quoted where the paper fixes them. This is the opposite of a sense entry in the tag table, which is the tagger's sentence about how the paper uses a term. Where a concept entry could not be grounded in the paper's words, the entry says so on its own row.

Other fields define these differently the same word, defined another way in another discipline
echo chamber 4 fields · engagement 4 fields · content analysis 3 fields · statistical-significance 2 fields

Tags on this paper

Every tag the record carries, each linking to every other paper in the corpus that carries it. A tag appears here whether or not its words occur in the article — the spans below are only the ones a sentence in this paper licenses. Of the 9 concept tags on this paper, 6 are grounded in a quoted sentence.

echo chamber political polarization social network content analysis gatekeeper media sources leaning consumption variance price of bipartisanship content and network are measured JOINTLY at the level of the individual user, rather than content consumption alone, and the authors state that as the study's distinguishing move POLITICAL LEANING IS NOT INFERRED FROM THE TEXT AT ALL: scoring short snippets is called very challenging, so the leaning is inherited from an externally supplied per-domain ground truth of news organisations and that borrowed score has a stated meaning of its own - the FRACTION OF FACEBOOK USERS VISITING A DOMAIN WHO IDENTIFY THEMSELVES AS CONSERVATIVE ON THEIR PROFILE - which the authors read as the domain having a conservative or liberal bent in its coverage the measurement is deliberately restricted to what can be scored: only tweets carrying a link to a news organisation with a known and independently derived leaning are counted at all CONSUMPTION IS DEFINED THROUGH THE NETWORK: a user's produced content is the tweets they post, and their consumed content is the tweets posted by the accounts they follow partisanship is given a PARAMETERISED definition rather than a threshold - a user is delta-partisan when their production polarity lies within delta of either extreme - and the authors state the nesting property that follows, so a claim at one delta implies the claim at every larger one VARIANCE IS MEASURED ALONGSIDE THE MEAN over the same set of tweets, with the stated objective of quantifying the RANGE of opinions a user's produced content covers FIVE NON-POLITICAL DATASETS ARE COLLECTED AS A BASELINE for the political ones - tbt, ff, gameofthrones, love, foodporn - each built from one hashtag by parsing an archive, filtering to users with at least five tweets, and then taking all of those users' tweets automated accounts are excluded by minimum AND maximum thresholds on tweets per day, followers and friends, together with a requirement that the account be at least one year old at collection time the paper STIPULATES 'gatekeeper' against the established sense and says so: in communication studies the term names news media sources acting as filters, and here it names an individual user who receives content from both leanings but produces only one users political network Twitter opinions partisan discourse engagement production consumption political leaning correlation effect-size effect size p-value statistical-significance statistically significant observational-study

Method, as described: observational-data-analysis

Legend

relation to other work	`claim_relations`	how this paper stands to another: agrees, contradicts, extends, qualifies
claim type	`claim_type`	the shape of the claim: existence, mechanism, method, critique, prediction, null
concept edge	`concept_edges`	an asserted relation between two concepts, with the sentence asserting it
concept	`concepts`	an idea the paper works with, quoted where the paper uses it
content tag	`content_tags`	a finding, definition, quantity, statistic or variable named in the paper
control	`controls`	an experiment run to eliminate a rival explanation
limitation	`limitations`	what the paper says its evidence cannot support
mechanism	`mechanisms`	how the reported effect is said to come about
method	`method`	how the paper produced its evidence
phenomenon	`phenomenon`	the effect or regularity under study
sense	`senses`	a distinct use of a term, quoted where the paper fixes it
unrecordable relation	`unhoused_relations`	a relation the paper asserts that this vocabulary cannot express, with the reason

The paper

The full text is not reproduced here. This article is not cleared for redistribution, so the page carries the tag layer only. Its evidence sentences are withheld; the grounding status remains with each tag, and the article itself is at https://arxiv.org/abs/1801.01665. The reading view exists for the papers whose licence permits it.

Every tag on this page

claim_relations 5 · claim_type 1 · concept_edges 2 · concepts 6 · content_tags 11 · controls 1 · limitations 11 · mechanisms 10 · method 1 · phenomenon 1 · senses 3 · unhoused_relations 1

Relations on this page carry a quotation for the claim. Where a relation was separately evidenced — and so tested against the vocabulary for its type — the row says so; none of 2 relations here carry that mark. The rest are the tagger’s reading of the sentence quoted beside them.

facet	tag	field	conf.	whose words
claim_type	existence Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_type`		the paper's words
phenomenon	political echo chambers on social media Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`phenomenon`		the paper's words
method	observational-study Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: observational-study	`method`		the paper's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: content and network are measured JOINTLY at the level of the individual user, rather than content consumption alone, and the authors state that as the study's distinguishing move	`mechanisms[0]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. about this quote: 2026-08-16: THIS QUOTE IS TRUNCATED MID-SENTENCE BECAUSE THE FILE INTERRUPTS IT. The staged text continues "...news organizations with 6https://en.wikipedia.org/... 7http://www.bbc.com/... 8https://www.nytimes.com/..." - three footnote URLs are spliced between 'with' and the rest of the clause, which resumes as 'a presence on social media obtained from Bakshy et al.' The span stops at the last word before the splice. The sentence is not quotable in full from this file without quoting three URLs in the middle of it. also in: POLITICAL LEANING IS NOT INFERRED FROM THE TEXT AT ALL: scoring short snippets is called very challenging, so the leaning is inherited from an externally supplied per-domain ground truth of news organisations	`mechanisms[1]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: and that borrowed score has a stated meaning of its own - the FRACTION OF FACEBOOK USERS VISITING A DOMAIN WHO IDENTIFY THEMSELVES AS CONSERVATIVE ON THEIR PROFILE - which the authors read as the domain having a conservative or liberal bent in its coverage	`mechanisms[2]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the measurement is deliberately restricted to what can be scored: only tweets carrying a link to a news organisation with a known and independently derived leaning are counted at all	`mechanisms[3]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: CONSUMPTION IS DEFINED THROUGH THE NETWORK: a user's produced content is the tweets they post, and their consumed content is the tweets posted by the accounts they follow	`mechanisms[4]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: partisanship is given a PARAMETERISED definition rather than a threshold - a user is delta-partisan when their production polarity lies within delta of either extreme - and the authors state the nesting property that follows, so a claim at one delta implies the claim at every larger one	`mechanisms[5]`	0.95	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: VARIANCE IS MEASURED ALONGSIDE THE MEAN over the same set of tweets, with the stated objective of quantifying the RANGE of opinions a user's produced content covers	`mechanisms[6]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: FIVE NON-POLITICAL DATASETS ARE COLLECTED AS A BASELINE for the political ones - tbt, ff, gameofthrones, love, foodporn - each built from one hashtag by parsing an archive, filtering to users with at least five tweets, and then taking all of those users' tweets	`mechanisms[7]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: automated accounts are excluded by minimum AND maximum thresholds on tweets per day, followers and friends, together with a requirement that the account be at least one year old at collection time	`mechanisms[8]`	0.85	the tagger's words
mechanisms	mechanisms Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: the paper STIPULATES 'gatekeeper' against the established sense and says so: in communication studies the term names news media sources acting as filters, and here it names an individual user who receives content from both leanings but produces only one	`mechanisms[9]`	0.95	the tagger's words
limitations	political leaning is measured only from tweets that link to news sources of known, independently-derived leaning, not the message content itself Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: every political-leaning measurement in the study: WE CONSIDER ONLY MESSAGES THAT CONTAIN A LINK TO AN ONLINE NEWS ORGANIZATION WITH A KNOWN AND INDEPENDENTLY DERIVED POLITICAL [leaning] - users without such links are unmeasured	`limitations[0]`		the tagger's words
limitations	All data come from Twitter and are only a sample of social-media discussion. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the generalisation to political discourse at large: all data come from Twitter and are only a sample of social-media discussion	`limitations[1]`		the tagger's words
limitations	Results are drawn from politically-savvy users and should not be assumed to generalise to the general public. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the network measured: the analysis rests on the retweet and follow graph available through the API, not on the full communication structure	`limitations[2]`		the tagger's words
limitations	The polarity measures depend on externally supplied political labels for news sources. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: every polarity score: OUR PRODUCTION AND CONSUMPTION SCORES RELY ON EXTERNAL LABELING OF NEWS SOURCES ALONG A POLITICAL AXIS	`limitations[3]`		the tagger's words
limitations	Following is used as a proxy for actual consumption; users may not read everything their neighbours post. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: every consumption measure: OUR ANALYSIS ASSUMES THAT EACH USER CONSUMES ALL CONTENT PRODUCED BY ALL THEIR NEIGHBORS - following stands in for reading	`limitations[4]`		the tagger's words
limitations	Some articles from the scored news domains may not be political. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the political-content assumption: NOT ALL NEWS ARTICLES FROM THE NEWS SOURCES WE BASE THE POLARITY MEASURES [on] ARE POLITICAL	`limitations[5]`		the tagger's words
limitations	The causal relations between selective exposure, biased assimilation, algorithmic filtering and echo chambers are not addressed. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: any causal reading of echo chambers: UNDERSTANDING HOW ALL THESE PHENOMENA INTERACT WITH EACH OTHER AND THE PRECISE CAUSALITY RELATIONS IS BEYOND THE SCOPE OF THIS PAPER	`limitations[6]`		the tagger's words
limitations	The literature has no consensus definition of the paper's central term, so the authors chose one. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the finding that echo chambers are prevalent: the authors state there is no consensus on a formal definition of an echo chamber in the literature and opt for their own, under which an echo chamber exists when the leaning of content a user receives agrees with the leaning of what they share	`limitations[7]`	1.0	the tagger's words
limitations	A term is borrowed from another field with its unit of analysis changed, which the authors state. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: any comparison with the gatekeeping literature: in media and communication studies gatekeepers are media sources acting as filters, whereas here they are individual users identified by their joint consumption and production leaning	`limitations[8]`	1.0	the tagger's words
limitations	A second definition of the same category was tested and its results not presented. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: the gatekeeper results reported here: the authors also tested a different definition - high consumption variance with low production variance - found the results almost identical, and did not present them explicitly	`limitations[9]`	1.0	the tagger's words
limitations	What the identified users are actually doing is left open by the authors. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. what this limits: any interpretation of the gatekeeper class: the authors say it is not clear from their analysis what such users are doing, so the label marks a position on two measures and not a motive	`limitations[10]`	1.0	the tagger's words
controls	ten-fold cross-validation of the partisan and gatekeeper classification model Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. eliminates: an accuracy figure earned on the same data the classifier was fitted to · outcome (stated by the tagger, no quotation): held	`controls[0]`	0.85	the tagger's words
concepts	echo chamber Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: echo chamber	`concepts[0]`		the paper's words
concepts	gatekeeper Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: gatekeeper	`concepts[4]`		the paper's words
concepts	media sources Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: media sources	`concepts[5]`		the paper's words
concepts	leaning Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: leaning	`concepts[6]`		the paper's words
concepts	consumption variance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: consumption variance	`concepts[7]`		the paper's words
concepts	price of bipartisanship Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: price of bipartisanship	`concepts[8]`		the paper's words
unhoused_relations	follow → content consumption Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. THE INDEXING / PROXY RELATION - 'from' STANDS IN FOR 'to'. We have no type for it: 'causes' asserts production, and 'operationalised-as' says the authors CHOSE a measure, whereas a proxy claim says THIS STANDS IN FOR WHAT WE ACTUALLY CARE ABOUT AND WE KNOW IT IS NOT THE SAME THING. Measured at 8% of papers. A measurement substitution stated plainly: 'we use the “follow” relationship as a proxy for the actual content consumption'. The word 'actual' is doing the same work as amodei2016's 'really care about' - the authors marking the distance between what they measured and what they meant.	`unhoused_relations[0]`		the tagger's words
senses	an echo chamber - AS AGREEMENT BETWEEN TWO PER-USER SCORES: it exists, for this paper, when the leaning of the content a user receives agrees with the leaning of what they share; not a group, not a network structure, not an isolation measure, but a correlation computed per user - and the authors adopt it because the literature offers no consensus formal definition to inherit Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[0]`	1.0	the tagger's words
senses	a gatekeeper - AN INDIVIDUAL USER, NOT A MEDIA SOURCE: communication studies gives the word to institutions that filter what passes into a channel, and this paper reassigns it to a person at a particular position on two scores, stating the earlier sense and supplying a bridging argument - that such users block information from one side, and hence can be considered gatekeepers Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[1]`	1.0	the tagger's words
senses	leaning - A STIPULATED SCORE, WITH ITS OWN SYNONYMS NAMED IN THE FOOTNOTE THAT STIPULATES IT: the authors define it as a score quantifying alignment with one political side and list the terms the literature uses for the same thing, so four words - leaning, ideology, polarity, ideological stance - are declared interchangeable by the paper itself Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`senses[2]`	1.0	the tagger's words
claim_relations	extends → the study of political polarization and echo chambers Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[0]`		the tagger's words
claim_relations	builds-on → the latent space model of Barberá et al. [7] Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[1]`		the tagger's words
claim_relations	builds-on → the news-source leaning scores and hard/soft news classifier of Bakshy et al. [4] Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[2]`		the tagger's words
claim_relations	replicates → Barberá [6] on higher polarization of retweet networks for political topics Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[3]`		the tagger's words
claim_relations	extends → prior echo-chamber studies that measure either content or network alone Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`claim_relations[4]`		the tagger's words
concept_edges	echo chamber —operationalised-as→ leaning Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. strength of the relation: 1 also in: echo chamber · leaning	`concept_edges[0]`		the tagger's words
concept_edges	gatekeeper —contrasted-with→ media sources Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span defines gatekeepers differently in media studies and in this study; contrasted-with is a loose reading. also in: gatekeeper · media sources	`concept_edges[1]`		the tagger's words
content_tags	Twitter users mostly see political opinions matching their own. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.findings[0]`		the tagger's words
content_tags	Engagement is measured as all content that a user clicks. Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above.	`content_tags.findings[1]`		the tagger's words
content_tags	political leaning Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: political leaning	`content_tags.variables[0]`		the tagger's words
content_tags	echo chamber Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. about this quote: QUOTE REPAIRED: the extractor split a hyphen-space and the quote was recorded faithfully with the damage in it, which made it unanchorable. The repaired string is an EXACT SUBSTRING of the staged text - that is why it was accepted, not because a rule produced it. The text as originally recorded is kept in evidence as extracted. also in: echo chamber	`content_tags.definitions[0]`		the tagger's words
content_tags	production Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: production	`content_tags.definitions[2]`		the tagger's words
content_tags	consumption Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: consumption	`content_tags.definitions[3]`		the tagger's words
content_tags	engagement Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: engagement	`content_tags.definitions[4]`		the tagger's words
content_tags	correlation Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. about this quote: QUOTE RECOVERED FROM THE PAPER'S OWN CHARACTERS. The recorded quote was LETTERS-ONLY IDENTICAL to this stretch of the staged text but not an exact substring of it - spaces, hyphens, ligature glyphs or mathematical operators differed, so it could never anchor. This is the file's own text between the same two letters: not produced by a rule about the damage, copied out of the file. Round-trip checked (the recovered span is letters-only equal to the original) and length-checked. The text as originally recorded is kept in evidence as extracted. also in: correlation	`content_tags.statistics[1]`		the tagger's words
content_tags	effect-size Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: effect-size	`content_tags.statistics[2]`		the tagger's words
content_tags	p-value Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. about this quote: QUOTE RECOVERED FROM THE PAPER'S OWN CHARACTERS. The recorded quote was LETTERS-ONLY IDENTICAL to this stretch of the staged text but not an exact substring of it - spaces, hyphens, ligature glyphs or mathematical operators differed, so it could never anchor. This is the file's own text between the same two letters: not produced by a rule about the damage, copied out of the file. Round-trip checked (the recovered span is letters-only equal to the original) and length-checked. The text as originally recorded is kept in evidence as extracted. also in: p-value	`content_tags.statistics[3]`		the tagger's words
content_tags	statistical-significance Quotation withheld — this record is not cleared for redistribution. The sentence is in the paper at the link above. also in: statistical-significance	`content_tags.statistics[4]`		the tagger's words

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