Auditing the Auditors: Does Community-based Moderation Get It Right?
Pith reviewed 2026-05-21 11:24 UTC · model grok-4.3
The pith
X's Community Notes auditing ties user eligibility to agreement with the final outcome, causing minority contributors to conform and reducing participation on controversial topics.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
In X's Community Notes after September 2022, consensus-based auditing that conditions participation on agreement with the eventual aggregate leads to minority contributors' evaluations drifting toward the majority and their participation share declining on controversial topics. A behavioral model formalizes contributors trading private beliefs against expected penalties for disagreement. The proposed two-stage auditing and aggregation algorithm first accounts for differences across content and contributors, then weights each contributor by the stability of their residuals relative to the latent-factor model; contributors with consistently informative evaluations receive greater influence, as
What carries the argument
The two-stage stability-weighted aggregation algorithm that first adjusts for content and contributor differences then assigns influence according to how predictable a contributor's evaluations remain relative to the latent-factor model.
If this is right
- Minority contributors maintain higher participation shares on topics with high disagreement.
- Aggregate predictions of misleading content improve on data not used to fit the model.
- Evaluations that consistently deviate from the majority but remain stable over time gain influence.
- The system avoids reducing the weight of independent signals on controversial items.
Where Pith is reading between the lines
- Similar stability-based weighting could be tested on other platforms that currently reward agreement with final labels.
- The method may preserve viewpoint diversity even when the true label is uncertain.
- Live A/B deployment on Community Notes could measure whether minority participation rebounds after switching auditing rules.
Load-bearing premise
The stability of a contributor's past residuals relative to a latent-factor model serves as a reliable proxy for how informative their future evaluations will be, independent of whether they match the final consensus.
What would settle it
Re-running the two-stage algorithm on a held-out portion of Community Notes data and finding no improvement in out-of-sample predictive accuracy compared with consensus-based aggregation would falsify the performance claim.
Figures
read the original abstract
Online social platforms increasingly rely on crowd-sourced systems to label misleading content at scale, but these systems must both aggregate users' evaluations and decide whose evaluations to trust. To address the latter, many platforms audit users by rewarding agreement with the final aggregate outcome, a design we term consensus-based auditing. We analyze the consequences of this design in X's Community Notes, which in September 2022 adopted consensus-based auditing that ties users' eligibility for participation to agreement with the eventual platform outcome. We find evidence of strategic conformity: minority contributors' evaluations drift toward the majority and their participation share falls on controversial topics, where independent signals matter most. We formalize this mechanism in a behavioral model in which contributors trade off private beliefs against anticipated penalties for disagreement. Motivated by these findings, we propose a two-stage auditing and aggregation algorithm that weights contributors by the stability of their past residuals rather than by agreement with the majority. The method first accounts for differences across content and contributors, and then measures how predictable each contributor's evaluations are relative to the latent-factor model. Contributors whose evaluations are consistently informative receive greater influence in aggregation, even when they disagree with the prevailing consensus. In the Community Notes data, this approach improves out-of-sample predictive performance while avoiding penalization of disagreement.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper examines X's Community Notes system, documenting strategic conformity under consensus-based auditing: minority contributors' ratings drift toward the majority and their participation declines on controversial topics. It formalizes this in a behavioral model and proposes a two-stage algorithm that first fits a latent-factor model to account for content and contributor differences, then weights contributors by the stability of their residuals relative to that model. The central empirical claim is that this stability-weighted aggregator improves out-of-sample predictive performance on Community Notes data while avoiding penalization of disagreement.
Significance. If the two-stage method genuinely delivers out-of-sample gains without mechanically down-weighting informative minority signals, the result would be relevant for platform design of crowd-sourced moderation. The behavioral model and observational evidence on conformity provide a useful starting point, though the strength of the performance claim depends on resolving the data-splitting and model-fitting details.
major comments (3)
- [Abstract and method section] The description of the two-stage algorithm (abstract and §4) does not state whether the latent-factor model is estimated on the full panel (including the eventual consensus ratings used to define eligibility) or only on training data. If the former, residuals and stability scores will absorb majority-driven patterns, undermining both the 'avoids penalization of disagreement' claim and the reported out-of-sample improvement.
- [Empirical results section] The out-of-sample predictive performance comparison lacks explicit baseline specifications, train/test split details, and controls for post-hoc tuning of the stability threshold or weighting function. Without these, it is difficult to rule out that the reported gains are driven by in-sample fitting rather than genuine generalization.
- [§3] The behavioral model in §3 assumes contributors trade off private beliefs against anticipated penalties, but the empirical test of strategic conformity does not report robustness checks that separate selection into participation from changes in rating behavior conditional on participating.
minor comments (2)
- [Method] Notation for the latent-factor model and residual stability metric should be defined more explicitly with equations rather than prose descriptions.
- [Figures] Figure captions and axis labels for the conformity and participation results could be expanded to clarify the exact sample restrictions and time windows used.
Simulated Author's Rebuttal
We thank the referee for their constructive and detailed feedback. We address each major comment below with clarifications on our current implementation and commitments to revisions that improve transparency and robustness without altering the core claims.
read point-by-point responses
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Referee: [Abstract and method section] The description of the two-stage algorithm (abstract and §4) does not state whether the latent-factor model is estimated on the full panel (including the eventual consensus ratings used to define eligibility) or only on training data. If the former, residuals and stability scores will absorb majority-driven patterns, undermining both the 'avoids penalization of disagreement' claim and the reported out-of-sample improvement.
Authors: The latent-factor model is estimated only on training data within each cross-validation fold, ensuring residuals and stability scores are computed without access to test-set outcomes or the final consensus ratings. This design prevents absorption of majority-driven patterns. We will revise the abstract and §4 to state this explicitly, add pseudocode for the procedure, and include a note confirming no information leakage from eligibility definitions. revision: yes
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Referee: [Empirical results section] The out-of-sample predictive performance comparison lacks explicit baseline specifications, train/test split details, and controls for post-hoc tuning of the stability threshold or weighting function. Without these, it is difficult to rule out that the reported gains are driven by in-sample fitting rather than genuine generalization.
Authors: We will expand the empirical results section with explicit details on temporal train/test splits (e.g., 70/30 by note creation date), a full set of baselines (unweighted mean, agreement-weighted, and simple majority), and sensitivity analyses for the stability threshold and weighting function. All hyperparameters are selected via training-data cross-validation only; we will report these controls to demonstrate generalization. revision: yes
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Referee: [§3] The behavioral model in §3 assumes contributors trade off private beliefs against anticipated penalties, but the empirical test of strategic conformity does not report robustness checks that separate selection into participation from changes in rating behavior conditional on participating.
Authors: Our current tests already document both participation decline and rating drift. We will add a robustness check limited to contributors active on both controversial and non-controversial notes, showing rating conformity persists conditional on continued participation. This directly addresses selection effects while preserving the behavioral model's interpretation. revision: partial
Circularity Check
No significant circularity detected
full rationale
The paper proposes a two-stage algorithm that first fits a latent-factor model to account for content and contributor differences, then weights by stability of past residuals relative to that model. It explicitly evaluates this on out-of-sample predictive performance in the Community Notes data and contrasts it with consensus-based auditing. No equations or descriptions in the abstract or described chain show the stability metric or performance gain reducing to a fit on the evaluation data itself, nor any self-definitional loop, self-citation load-bearing premise, or renaming of known results. The behavioral model of strategic conformity is presented as an independent empirical observation. The derivation chain remains self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
free parameters (2)
- latent-factor dimensionality
- stability threshold or weighting function
axioms (1)
- domain assumption Contributors trade off private beliefs against anticipated penalties for disagreement.
Lean theorems connected to this paper
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IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
The method first accounts for differences across content and contributors, and then measures how predictable each contributor’s evaluations are relative to the latent-factor model... inverse-variance weights
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IndisputableMonolith/Foundation/BranchSelection.leanbranch_selection unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
weighted matrix factorization... 1/σ̂²u ... feasible generalized least squares
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Dahleh, Ilan Lobel, and Asuman Ozdaglar
Daron Acemoglu, Munther A. Dahleh, Ilan Lobel, and Asuman Ozdaglar. Bayesian learning in social networks. The Review of Economic Studies, 78(4):1201–1236, 2011
work page 2011
-
[2]
Fast and slow learning from reviews
Daron Acemoglu, Ali Makhdoumi, Azarakhsh Malekian, and Asu Ozdaglar. Fast and slow learning from reviews. Econometrica, 90(2):775–810, 2022
work page 2022
-
[3]
A model of online misinformation.Review of Economic Studies, 91(6):3117–3150, 2024
Daron Acemoglu, Asuman Ozdaglar, and James Siderius. A model of online misinformation.Review of Economic Studies, 91(6):3117–3150, 2024
work page 2024
-
[4]
A. C. Aitken. Iv.—on least squares and linear combination of observations.Proceedings of the Royal Society of Edinburgh, 55:42–48, 1936
work page 1936
-
[5]
Jennifer Allen, Cameron Martel, and David G Rand. Birds of a feather don’t fact-check each other: Partisanship and the evaluation of news in twitter’s birdwatch crowdsourced fact-checking program. InProceedings of the 2022 CHI Conference on Human Factors in Computing Systems, CHI ’22, New York, NY , USA, 2022. Association for Computing Machinery
work page 2022
-
[6]
Jennifer Allen, Duncan J Watts, and David G Rand. Quantifying the impact of misinformation and vaccine- skeptical content on facebook.Science, 384(6699):eadk3451, 2024
work page 2024
- [7]
-
[8]
Panel data models with interactive fixed effects.Econometrica, 77(4):1229–1279, 2009
Jushan Bai. Panel data models with interactive fixed effects.Econometrica, 77(4):1229–1279, 2009
work page 2009
- [9]
-
[10]
Zhang, Connie Moon Sehat, and Tanushree Mitra
Md Momen Bhuiyan, Amy X. Zhang, Connie Moon Sehat, and Tanushree Mitra. Investigating differences in crowdsourced news credibility assessment: Raters, tasks, and expert criteria.Proc. ACM Hum.-Comput. Interact., 4(CSCW2), October 2020
work page 2020
-
[11]
Nadia M Brashier, Gordon Pennycook, Adam J Berinsky, and David G Rand. Timing matters when correcting fake news.Proceedings of the National Academy of Sciences, 118(5):e2020043118, 2021
work page 2021
-
[12]
Raymond J. Carroll and David Ruppert. Robust estimation in heteroscedastic linear models.The Annals of Statistics, 10(2):429–441, 1982
work page 1982
-
[13]
Yuxin Chen, Yuejie Chi, Jianqing Fan, Cong Ma, and Yuling Yan. Noisy matrix completion: Understanding statistical guarantees for convex relaxation via nonconvex optimization.SIAM journal on optimization, 30(4):3098– 3121, 2020
work page 2020
-
[14]
Locking and unlocking the ability to write notes
Community Notes Guide – X. Locking and unlocking the ability to write notes. https://communitynotes.x. com/guide/en/contributing/writing-ability, n.d. Accessed: 2025-08-30
work page 2025
-
[15]
Community Notes Guide – X. Rating and writing impact. https://communitynotes.x.com/guide/en/ contributing/writing-and-rating-impact, n.d. Accessed: 2025-08-30
work page 2025
-
[16]
Aggregation of consumer ratings: an application to yelp
Weijia Dai, Ginger Jin, Jungmin Lee, and Michael Luca. Aggregation of consumer ratings: an application to yelp. com.Quantitative Marketing and Economics, 16(3):289–339, 2018
work page 2018
-
[17]
Alexander Philip Dawid and Allan M Skene. Maximum likelihood estimation of observer error-rates using the em algorithm.Journal of the Royal Statistical Society: Series C (Applied Statistics), 28(1):20–28, 1979
work page 1979
-
[18]
Diffusion of community fact-checked misinformation on twitter
Chiara Patricia Drolsbach and Nicolas Pröllochs. Diffusion of community fact-checked misinformation on twitter. Proceedings of the ACM on Human-Computer Interaction, 7(CSCW2):1–22, 2023
work page 2023
-
[19]
Community notes increase trust in fact-checking on social media.PNAS nexus, 3(7):pgae217, 2024
Chiara Patricia Drolsbach, Kirill Solovev, and Nicolas Pröllochs. Community notes increase trust in fact-checking on social media.PNAS nexus, 3(7):pgae217, 2024
work page 2024
-
[20]
Erik Eyster and Matthew Rabin. Naive herding in rich-information settings.American economic journal: microeconomics, 2(4):221–243, 2010
work page 2010
-
[21]
Boi Faltings and Goran Radanovic.Game theory for data science: Eliciting truthful information. Springer Nature, 2022
work page 2022
-
[22]
Vivek Farias, Andrew A Li, and Tianyi Peng. Uncertainty quantification for low-rank matrix completion with heterogeneous and sub-exponential noise. InInternational Conference on Artificial Intelligence and Statistics, pages 1179–1189. PMLR, 2022
work page 2022
- [23]
-
[24]
Yang Gao, Maggie Mengqing Zhang, and Huaxia Rui. Can crowdchecking curb misinformation? evidence from community notes.Information Systems Research, 2025
work page 2025
-
[25]
Tilmann Gneiting and Adrian E Raftery. Strictly proper scoring rules, prediction, and estimation.Journal of the American Statistical Association, 102(477):359–378, 2007
work page 2007
-
[26]
Incentives and truthful reporting in consensus-centric crowdsourcing
Eric Horvitz. Incentives and truthful reporting in consensus-centric crowdsourcing. Technical report, Microsoft Research, 2012
work page 2012
-
[27]
Matthew Jackson and Stephen Nei. Finding the wise and the wisdom in a crowd: Estimating underlying qualities of reviewers and items.American Economic Review, 111(3):1001–1024, 2021
work page 2021
-
[28]
Uku Kangur, Roshni Chakraborty, and Rajesh Sharma. Who checks the checkers? exploring source credibility in twitter’s community notes.arXiv preprint arXiv:2406.12444, 2024
-
[29]
David Karger, Sewoong Oh, and Devavrat Shah. Iterative learning for reliable crowdsourcing systems.Advances in neural information processing systems, 24, 2011
work page 2011
-
[30]
Trustworthy human computation: a survey
Hisashi Kashima, Satoshi Oyama, Hiromi Arai, and Junichiro Mori. Trustworthy human computation: a survey. Artificial Intelligence Review, 57(12):322, 2024
work page 2024
-
[31]
Putting peer prediction under the micro (economic) scope and making truth-telling focal
Yuqing Kong, Katrina Ligett, and Grant Schoenebeck. Putting peer prediction under the micro (economic) scope and making truth-telling focal. InInternational Conference on Web and Internet Economics, pages 251–264. Springer, 2016
work page 2016
-
[32]
Machine-learning aided peer prediction
Yang Liu and Yiling Chen. Machine-learning aided peer prediction. InProceedings of the 2017 ACM Conference on Economics and Computation, EC ’17, page 63–80, New York, NY , USA, 2017. Association for Computing Machinery
work page 2017
-
[33]
Jan Lorenz, Heiko Rauhut, Frank Schweitzer, and Dirk Helbing. How social influence can undermine the wisdom of crowd effect.Proceedings of the national academy of sciences, 108(22):9020–9025, 2011
work page 2011
-
[34]
Introducing community notes — adding context to posts
Meta Platforms, Inc. Introducing community notes — adding context to posts. https://www.meta.com/technologies/community-notes/?srsltid= AfmBOoqGYuB01StOhwvVzji0toKNwMWsuS3OurkU7X3c5L2AvsifdBYC, 2025. Accessed: 2025-11-17
work page 2025
-
[35]
Eliciting informative feedback: The peer-prediction method
Nolan Miller, Paul Resnick, and Richard Zeckhauser. Eliciting informative feedback: The peer-prediction method. Management Science, 51(9):1359–1373, 2005
work page 2005
-
[36]
Hyungsik Roger Moon and Martin Weidner. Linear regression for panel with unknown number of factors as interactive fixed effects.Econometrica, 83(4):1543–1579, 2015
work page 2015
-
[37]
Social influence bias: A randomized experiment.Science, 341(6146):647–651, 2013
Lev Muchnik, Sinan Aral, and Sean J Taylor. Social influence bias: A randomized experiment.Science, 341(6146):647–651, 2013
work page 2013
-
[38]
University of Chicago Press, 1974
Elisabeth Noelle-Neumann.The Spiral of Silence: A Theory of Public Opinion. University of Chicago Press, 1974
work page 1974
-
[39]
Juan Perdomo, Tijana Zrnic, Celestine Mendler-Dünner, and Moritz Hardt. Performative prediction. InInterna- tional Conference on Machine Learning, pages 7599–7609. PMLR, 2020
work page 2020
-
[40]
Twitter expands its crowdsourced fact-checking program Birdwatch ahead of US midterms, September
Sarah Perez. Twitter expands its crowdsourced fact-checking program Birdwatch ahead of US midterms, September
-
[41]
Accessed: 2025-09-16
work page 2025
-
[42]
Twitter is making its crowdsourced fact-checks visible to all U.S
Sarah Perez. Twitter is making its crowdsourced fact-checks visible to all U.S. users with Birdwatch expansion, October 2022. Accessed: 2025-09-16
work page 2022
-
[43]
Sarah Perez. Bluesky adds ‘anti-toxicity’ tools and aims to integrate ‘a community notes-like’ feature in the future. TechCrunch, 2024. Accessed: 2025-11-17
work page 2024
-
[44]
A bayesian truth serum for subjective data.Science, 306(5695):462–466, 2004
Drazen Prelec. A bayesian truth serum for subjective data.Science, 306(5695):462–466, 2004
work page 2004
-
[45]
Learning from crowds.Journal of machine learning research, 11(4), 2010
Vikas C Raykar, Shipeng Yu, Linda H Zhao, Gerardo Hermosillo Valadez, Charles Florin, Luca Bogoni, and Linda Moy. Learning from crowds.Journal of machine learning research, 11(4), 2010
work page 2010
-
[46]
Thomas Renault, Mohsen Mosleh, and David G Rand. Republicans are flagged more often than democrats for sharing misinformation on x’s community notes.Proceedings of the National Academy of Sciences, 122(25):e2502053122, 2025
work page 2025
-
[47]
The influence limiter: provably manipulation-resistant recommender systems
Paul Resnick and Rahul Sami. The influence limiter: provably manipulation-resistant recommender systems. In Proceedings of the 2007 ACM Conference on Recommender Systems, RecSys ’07, page 25–32, New York, NY , USA, 2007. Association for Computing Machinery. 17 APREPRINT- MARCH20, 2026
work page 2007
-
[48]
Informed truthfulness in multi-task peer prediction
Victor Shnayder, Arpit Agarwal, Rafael Frongillo, and David C Parkes. Informed truthfulness in multi-task peer prediction. InProceedings of the 2016 ACM Conference on Economics and Computation, pages 179–196, 2016
work page 2016
-
[49]
Isaac Slaughter, Axel Peytavin, Johan Ugander, and Martin Saveski. Community notes reduce engagement with and diffusion of false information online.Proceedings of the National Academy of Sciences, 122(38):e2503413122, 2025
work page 2025
-
[50]
Pathological outcomes of observational learning.Econometrica, 68(2):371–398, 2000
Lones Smith and Peter Sørensen. Pathological outcomes of observational learning.Econometrica, 68(2):371–398, 2000
work page 2000
-
[51]
Weighted low-rank approximations
Nathan Srebro and Tommi Jaakkola. Weighted low-rank approximations. InProceedings of the 20th international conference on machine learning (ICML-03), pages 720–727, 2003
work page 2003
-
[52]
Liangjun Su, Fa Wang, and Yiren Wang. Estimation and inference for unbalanced panel data models with interactive fixed effects.Journal of Econometrics, 255:106222, 2026
work page 2026
- [53]
-
[54]
Diverse perspectives can mitigate political bias in crowdsourced content moderation
Jacob Thebault-Spieker, Sukrit Venkatagiri, Naomi Mine, and Kurt Luther. Diverse perspectives can mitigate political bias in crowdsourced content moderation. InProceedings of the 2023 ACM Conference on Fairness, Accountability, and Transparency, pages 1280–1291, 2023
work page 2023
-
[55]
TikTok Pte. Ltd. Rolling out tiktok footnotes in the u.s. https://newsroom.tiktok.com/ rolling-out-tiktok-footnotes-in-the-us?lang=en, 2025. Accessed: 2025-11-17
work page 2025
-
[56]
Community notes: Documentation and source code powering community notes
Twitter, Inc. Community notes: Documentation and source code powering community notes. https://github. com/twitter/communitynotes, 2022
work page 2022
-
[57]
Generalized low rank models.Foundations and Trends in Machine Learning, 9(1):1–118, 2016
Madeleine Udell, Corinne Horn, Reza Zadeh, and Stephen Boyd. Generalized low rank models.Foundations and Trends in Machine Learning, 9(1):1–118, 2016
work page 2016
-
[58]
Sander Van Der Linden. Misinformation: susceptibility, spread, and interventions to immunize the public.Nature medicine, 28(3):460–467, 2022
work page 2022
-
[59]
Manipulation robustness of collaborative filtering.Management Science, 56(11):1911–1929, 2010
Benjamin Van Roy and Xiang Yan. Manipulation robustness of collaborative filtering.Management Science, 56(11):1911–1929, 2010
work page 1911
-
[60]
Introduction to the non-asymptotic analysis of random matrices., 2012
Roman Vershynin. Introduction to the non-asymptotic analysis of random matrices., 2012
work page 2012
-
[61]
Eugene Stanley, and Walter Quattrociocchi
Michela Del Vicario, Alessandro Bessi, Fabiana Zollo, Fabio Petroni, Antonio Scala, Guido Caldarelli, H. Eugene Stanley, and Walter Quattrociocchi. The spreading of misinformation online.Proceedings of the National Academy of Sciences, 113(3):554–559, 2016
work page 2016
-
[62]
The spread of true and false news online.Science, 359(6380):1146– 1151, 2018
Soroush V osoughi, Deb Roy, and Sinan Aral. The spread of true and false news online.Science, 359(6380):1146– 1151, 2018
work page 2018
-
[63]
Output agreement mechanisms and common knowledge
Bo Waggoner and Yiling Chen. Output agreement mechanisms and common knowledge. InProceedings of the AAAI Conference on Human Computation and Crowdsourcing, volume 2, pages 220–226, 2014
work page 2014
-
[64]
Jevin D. West and Carl T. Bergstrom. Misinformation in and about science.Proceedings of the National Academy of Sciences, 118(15):e1912444117, 2021
work page 2021
-
[65]
Peer prediction without a common prior
Jens Witkowski and David C Parkes. Peer prediction without a common prior. InProceedings of the 13th ACM Conference on Electronic Commerce, pages 964–981, 2012
work page 2012
-
[66]
X Community Notes Guide. Ranking notes. https://communitynotes.x.com/guide/en/ under-the-hood/ranking-notes, n.d. Accessed: 2025-08-30
work page 2025
-
[67]
X Corp. About community notes on x. https://help.x.com/en/using-x/community-notes, 2025. Ac- cessed: 2025-11-17
work page 2025
-
[68]
X Corp. / Community Notes Guide. Note ranking algorithm. https://communitynotes.x.com/guide/en/ under-the-hood/ranking-notes, n.d. Accessed: 2025-08-05
work page 2025
-
[69]
X (formerly Twitter) Community Notes Guide. Downloading data. https://communitynotes.x.com/guide/ en/under-the-hood/download-data, n.d. Accessed: 2025-08-30
work page 2025
-
[70]
Dora Zhao, Diyi Yang, and Michael S. Bernstein. Mapping the spiral of silence: Surveying unspoken opinions in online communities.arXiv preprint arXiv:2502.00952, 2025. 18 APREPRINT- MARCH20, 2026 A Guide to the Appendix This Appendix has two goals. First, it provides the empirical implementation details and robustness analyses underlying the main-text res...
-
[71]
The user-side variables{(h u, fu)}U u=1 are independent of the note-side variables{(i n, gn)}N n=1
-
[72]
The noise variables ϵun are independent, mean-zero, σϵ-sub-Gaussian, and independent of all other latent variables (see e.g., [59] Definition 5.7)
-
[73]
Assumption 2(Conformity parameters).In addition to Assumption 1, assume: 1.m n are i.i.d
Each entry(u, n)is observed independently with probabilityp∈(0,1), andU≍N. Assumption 2(Conformity parameters).In addition to Assumption 1, assume: 1.m n are i.i.d. draws from a bounded distribution on a compact interval with positive finite variance. 2.ρ n :=ρ(c n)is a weakly decreasing function inc n
-
[74]
Assume that¯ρN →¯ρ∈[0,1]a deterministic constant
Let¯ρN =N −1P n ρn. Assume that¯ρN →¯ρ∈[0,1]a deterministic constant
-
[75]
For each noten, the random variablesm n andg n are independent. 36 APREPRINT- MARCH20, 2026 E.2 Private-Signal Reporting: Consistency of Note Helpfulness (Proof of Theorem 1) We first study the benchmark case in which contributors report their private signals, so the platform observes a noisy version of the latent signal matrix S=µ1 U 1⊤ N +h1 ⊤ N +1 U i⊤...
work page 2026
-
[76]
Now, we turn to proving upper bounds
Combining this with the lower bound onP u,n x2 un established above, we obtain with high probability X u,n ωunx2 un ≥c ′ U N(δµ)2 +N∥δh∥ 2 2 +U∥δi∥ 2 2 +N∥δf∥ 2 2 +U∥δg∥ 2 2 −C∥δf∥ 2 2∥δg∥2 2 −C∥δf∥ 4 2 for some constantsc ′, C >0. Now, we turn to proving upper bounds. Recall that it remains to upper bound the terms X u,n ωuny2 un, X u,n ωunϵunxun, X u,n ...
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[77]
SinceXis at most rank5, we have X u,n ωunϵunxun ≤ ∥Ω◦E∥ op · ∥X∥ ∗ ≤ √ 5∥Ω◦E∥ op · ∥X∥ F
Then, X u,n ωuny2 un ≤ X u,n y2 un = X u,n (δfuδgn)2 ≤ ∥δf∥ 2 2∥δg∥2 2 ≤ M(δ) 2 U N . SinceXis at most rank5, we have X u,n ωunϵunxun ≤ ∥Ω◦E∥ op · ∥X∥ ∗ ≤ √ 5∥Ω◦E∥ op · ∥X∥ F . Here, we slightly abuse notation and let Ω denote the matrix with entries ωun. Using the fact that ∥X∥2 F ≲M(δ) , Young’s inequality, and sub-Gaussian errors from Assumption 1, we ...
work page 2026
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