“Half the Truth is often a great Lie.”

 

– Benjamin Franklin

PennMAP

Penn Media Accountability Project

PennMAP is an interdisciplinary, nonpartisan research project of the Computational Social Science Lab at the University of Pennsylvania dedicated to enhancing media transparency and accountability at the scale of the entire information ecosystem.

Touchstone Publications

MISUNDERSTANDING THE HARMS OF ONLINE MISINFORMATION

QUANTIFYING THE IMPACT OF MISINFORMATION AND VACCINE SKEPTICAL-CONTENT ON FACEBOOK 

CAUSALLY ESTIMATING THE EFFECT OF YOUTUBE’S RECOMMENDER SYSTEM USING COUNTERFACTUAL BOTS

Data Dashboard:

Media Bias Detector

To measure and expose bias in the mainstream media, PennMAP is proud to launch the Media Bias Detector, which tracks and classifies the top stories published by a collection of prominent publishers spanning the political spectrum in close to real time.

DASHBOARDS

Media Bias Detector

News Consumption

YouTube Politics

Mission

Misinformation in media is believed to have harmful effects on public opinion, political polarization, and ultimately democratic decision making. And yet, much remains unknown regarding the prevalence of misinformation and its effects on society.

To address this problem, PennMAP is building technology to detect patterns of bias and misinformation in media from across the political spectrum and spanning television, radio, social media, and the broader web. We will also track consumption of information via television, desktop computers, and mobile devices, as well as its effects on individual and collective beliefs and understanding.

In collaboration with our data partners, we are also building a scalable data infrastructure to ingest, process, and analyze tens of terabytes of television, radio, and web content, as well as representative panels of roughly 100,000 media consumers over several years. While our initial focus is on the U.S., our hope is to scale this infrastructure to eventually cover other countries and languages other than English.

Commitment to Use-Inspired Research

We will share our insights through publications and interactive data visualizations, and will work with various stakeholders—including journalists, policy makers, and industry partners—to implement solutions. Aside from powering our own research, our infrastructure will support other research teams, thereby accelerating the pace of knowledge accumulation and enhancing its reliability.

In the News

Researcher Spotlight: CSSLab Members Present Work at Annenberg Workshop 

Researcher Spotlight: CSSLab Members Present Work at Annenberg Workshop 

Annenberg PhD student Neil Fasching and Postdoctoral researcher Jennifer Allen of the Computational Social Science Lab (CSSLab) recently presented their research on April 15th at the 2nd annual Center for Information Network Democracy Workshop: The Impact of AI on (Mis)Information. CIND is an initiative led by Annenberg faculty members Sandra González-Bailón and Yphtach Lelkes, focused on the impact of information ecosystems on democratic participation in the digital age.

Can Social Media Be Less Toxic?

Can Social Media Be Less Toxic?

In an era where online interactions can be both motivational and toxic, researchers from the Computational Social Science Lab (CSSLab) at the University of Pennsylvania are interested in what encourages prosocial behavior — acts of kindness, support, and cooperation — on social media.

People

Duncan Watts

Stevens University Professor
Penn Integrates Knowledge Professor

Homa Hosseinmardi

Associate Research Scientist

Amir Ghasemian

Affiliate Research Scientist
Yale University

David Rothschild

Affiliate Research Scientist
Microsoft Research

AMIR TOHIDI

Post-Doctoral Researcher

JENNIFER ALLEN

Post-Doctoral Researcher

Upasana Dutta

Ph.D. in Computer and Information Science

Samar Haider

Ph.D. in Computer and Information Science

Baird Howland

Ph.D. in Communications

Sam Wolken

Ph.D. in Communications and Political Science

Timothy Dorr

Ph.D. in Communications

CALVIN ISCH

Ph.D. in Communications

NEIL FASCHING

Ph.D. in Communications

People

Duncan Watts

Stevens University Professor
Penn Integrates Knowledge Professor

Homa Hosseinmardi

Associate Research Scientist

Amir Ghasemian

Affiliate Research Scientist
Yale University

David Rothschild

Affiliate Research Scientist
Microsoft Research

Coen Needell

Pre-Doctoral Researcher

Timothy Dorr

Ph.D. in Communications

Upasana Dutta

Ph.D. in Computer and Information Science

Samar Haider

Ph.D. in Computer and Information Science

Baird Howland

Ph.D. in Communications

Sam Wolken

Ph.D. in Communications and Political Science

Publications

Wang, Jenny S.; Haider, Samar; Tohidi, Amir; Gupta, Anushkaa; Zhang, Yuxuan; Callison-Burch, Chris; Rothschild, David; Watts, Duncan J.

Media Bias Detector: Designing and Implementing a Tool for Real-Time Selection and Framing Bias Analysis in News Coverage Unpublished

2025.

Abstract | Links | BibTeX

Wang, Jenny S.; Haider, Samar; Tohidi, Amir; Gupta, Anushkaa; Zhang, Yuxuan; Callison-Burch, Chris; Rothschild, David; Watts, Duncan J.

Media Bias Detector: Designing and Implementing a Tool for Real-Time Selection and Framing Bias Analysis in News Coverage Journal Article

In: CHI '25: Proceedings of the 2025 CHI Conference on Human Factors in Computing Systems, pp. 1-27, 2025.

Abstract | Links | BibTeX

Tohidi, Amir; Balietti, Stefano; Fraiberger, Samuel; Balietti, Anca

Divergence between predicted and actual perception of climate information Journal Article

In: PNAS Nexus, 2025.

Abstract | Links | BibTeX

Timothy Dörr, Timothy; Nagpal, Trisha; Watts, Duncan; Bail, Chris

A research agenda for encouraging prosocial behaviour on social media Journal Article

In: Nature Human Behaviour , 2025.

Abstract | Links | BibTeX

Liu, Naijia; Hu, Emily Xinlan; Savas, Yasemin; Baum, Matthew A.; Berinsky, Adam J.; Allison J.B. Chaney,; Lucas, Christopher; Mariman, Rei; Benedictis-Kessner, Justin de; Guess, Andrew M.; Knox, Dean; M., Stewart Brandon

Short-term exposure to filter-bubble recommendation systems has limited polarization effects: Naturalistic experiments on YouTube Journal Article

In: Proceedings of the National Academy of Sciences, vol. 122, iss. 8, 2025.

Abstract | Links | BibTeX

Isch, Calvin

Media bias in portrayals of mortality risks: Comparison of newspaper coverage to death rates Journal Article

In: Social Science and Medicine , vol. 364, 2025.

Abstract | Links | BibTeX

Fotouhi, Babak; Tohidi, Amir; Touserkani, Rouzbeh; Bushman, Brad J.

Trends of Violence in Movies During the Past Half Century Journal Article

In: Jama Pediatrics , 2024.

Abstract | Links | BibTeX

Li, Bryan; Haider, Samar; Luo, Fiona; Agashe, Adwait; Callison-Burch, Chris

BordIRlines: A Dataset for Evaluating Cross-lingual Retrieval Augmented Generation Proceedings Article

In: Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pp. 1-13, Association for Computational Linguistics, Miami, Florida, USA, 2024.

Abstract | Links | BibTeX

Li, Bryan; Haider, Samar; Callison-Burch, Chris

This Land is {Your, My} Land: Evaluating Geopolitical Biases in Language Models Proceedings Article

In: Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pp. 3855-3871, 2024.

Abstract | Links | BibTeX

Budak, Ceren; Nyhan, Brendan; Rothschild, David M.; Emily Thorson,; Watts, Duncan J.

Misunderstanding the harms of online misinformation Journal Article

In: Nature , vol. 630 , pp. 45-53, 2024.

Abstract | Links | BibTeX

Allen, Jennifer; Watts, Duncan J.; Rand, David G.

Quantifying the impact of misinformation and vaccine-skeptical content on Facebook Journal Article

In: Science, vol. 384, iss. 6699, 2024.

Abstract | Links | BibTeX

Hosseinmardi, Homa; Ghasemian, Amir; Rivera-Lanas, Miguel; Horta Ribeiro, Manoel; West, Robert; Watts, Duncan J.

Causally estimating the effect of YouTube’s recommender system using counterfactual bots Journal Article

In: PNAS, vol. 121, iss. 8, 2024.

Abstract | Links | BibTeX

Ribeiro, Manoel Horta; Hosseinmardi, Homa; West, Robert; Watts, Duncan J.

Deplatforming did not decrease Parler users’ activity on fringe social media Journal Article

In: PNAS Nexus, vol. 2, iss. 3, 2023.

Abstract | Links | BibTeX

Muise, Daniel; Hosseinmardi, Homa; Howland, Baird; Mobius, Markus; Rothschild, David; Watts, Duncan J.

Quantifying partisan news diets in Web and TV audiences Journal Article

In: Science Advances, vol. 8, iss. 28, 2022.

Abstract | Links | BibTeX

Balietti, Stefano; Getoor, Lise; Goldstein, Daniel G.; Watts, Duncan J.

Reducing opinion polarization: Effects of exposure to similar people with differing political views Journal Article

In: Proceedings of the National Academy of Sciences, vol. 118, no. 52, 2021.

Abstract | Links | BibTeX

Lifchits, George; Anderson, Ashton; Goldstein, Daniel G.; Hofman, Jake M.; Watts, Duncan J.

Success stories cause false beliefs about success Journal Article

In: Judgment and Decision Making, vol. 16, no. 6, pp. 1439-1463, 2021, ISSN: 1930-2975.

Abstract | Links | BibTeX

Konitzer, Tobias; Allen, Jennifer; Eckman, Stephanie; Howland, Baird; Mobius, Markus; Rothschild, David; Watts, Duncan J.

Comparing Estimates of News Consumption from Survey and Passively Collected Behavioral Data Journal Article

In: Public Opinion Quarterly, 2021.

Abstract | Links | BibTeX

Hosseinmardi, Homa; Ghasemian, Amir; Clauset, Aaron; Mobius, Markus; Rothschild, David M.; Watts, Duncan J.

Examining the consumption of radical content on YouTube Journal Article

In: Proceedings of the National Academy of Sciences, vol. 118, no. 32, 2021.

Abstract | Links | BibTeX

Allen, Jennifer; Mobius, Markus; Rothschild, David M.; Watts, Duncan J.

Research note: Examining potential bias in large-scale censored data Journal Article

In: Harvard Kennedy School (HKS) Misinformation Review, 2021.

Abstract | Links | BibTeX

Watts, Duncan J; Rothschild, David M; Mobius, Markus

Measuring the news and its impact on democracy Journal Article

In: Proceedings of the National Academy of Sciences, vol. 118, no. 15, 2021.

Abstract | Links | BibTeX

Allen, Jennifer; Howland, Baird; Mobius, Markus; Rothschild, David; Watts, Duncan J

Evaluating the fake news problem at the scale of the information ecosystem Journal Article

In: Science Advances, vol. 6, no. 14, pp. eaay3539, 2020.

Abstract | Links | BibTeX

Kao, Hsien-Te; Yan, Shen; Huang, Di; Bartley, Nathan; Hosseinmardi, Homa; Ferrara, Emilio

Understanding Cyberbullying on Instagram and Ask.fm via Social Role Detection Journal Article

In: Companion Proceedings of The 2019 World Wide Web Conference, pp. 183-188, 2019.

Abstract | Links | BibTeX

Ghasemian, Amir; Hosseinmardi, Homa; Clauset, Aaron

Evaluating overfit and underfit in models of network community structure Journal Article

In: IEEE Transactions on Knowledge and Data Engineering, vol. 32, no. 9, pp. 1722-1735, 2019.

Abstract | Links | BibTeX

Lazer, David M. J.; Baum, Matthew A.; Benkler, Yochai; Berinsky, Adam J.; Greenhill, Kelly M.; Menczer, Filippo; Metzger, Miriam J.; Nyhan, Brendan; Pennycook, Gordon; Rothschild, David; Schudson, Michael; Sloman, Steven A.; Sunstein, Cass R.; Thorson, Emily A.; Watts, Duncan J.; Zittrain, Jonathan L.

The science of fake news Journal Article

In: Science, vol. 359, no. 6380, pp. 1094-1096, 2018.

Links | BibTeX

Houghton, James P.; Siegel, Michael; Madnick, Stuart; Tounaka, Nobuaki; Nakamura, Kazutaka; Sugiyama, Takaaki; Nakagawa, Daisuke; Shirnen, Buyanjargal

Beyond Keywords: Tracking the evolution of conversational clusters in social media Journal Article

In: Sociological Methods & Research, vol. 48, no. 3, pp. 588-607, 2017.

Abstract | Links | BibTeX