“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
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
News On Climate Change Is More Persuasive Than Expected, Study Finds
Climate change is one of the most pressing challenges of our time, demanding urgent and effective action to mitigate its severe impacts. One barrier to effective climate change action is its polarizing nature largely driven by the media, as people prefer to consume news that aligns with their political beliefs. This tendency is especially strong among climate skeptics, who are more inclined to seek information that reinforces their views on climate change. In this context, communication—especially on social media—plays a crucial role in bridging cross-partisan boundaries. However, meaningful dialogue may be hampered if individuals do not believe these interactions will be effective.
From Cracks to Gardens: Creating a Thriving Social Media Through Research
Early advocates of social media believed that the creation of these platforms would lead to positive outcomes. When Facebook was launched in 2004, it was praised for its ability to “connect the entire world.” In hindsight, many of these ideals were optimistic at their time as social media platforms are often criticized for spreading hate and misinformation.
How the Media Distorts Perceptions on Chronic Disease Risks
Silent illnesses, or chronic diseases, contribute to 70% of deaths in the US annually and six in ten Americans suffer from at least one chronic condition. Despite this, coverage of this public health crisis is disproportionately overshadowed by sensational risks, including terrorism, homicide, and traffic accidents- incidents that are far more likely to grab readers’ attention.
In the News
News On Climate Change Is More Persuasive Than Expected, Study Finds
From Cracks to Gardens: Creating a Thriving Social Media Through Research
How the Media Distorts Perceptions on Chronic Disease Risks
Violent Language in Films Has Increased Since the 1970s: A New Study
Grumpy Voters Want Better Stories. Not Statistics
University of Pennsylvania Launches Penn Center on Media, Technology, and Democracy
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
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
Media bias in portrayals of mortality risks: Comparison of newspaper coverage to death rates Journal Article
In: Social Science and Medicine , vol. 364, 2025.
Trends of Violence in Movies During the Past Half Century Journal Article
In: Jama Pediatrics , 2024.
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.
Misunderstanding the harms of online misinformation Journal Article
In: Nature , vol. 630 , pp. 45-53, 2024.
Quantifying the impact of misinformation and vaccine-skeptical content on Facebook Journal Article
In: Science, vol. 384, iss. 6699, 2024.
Causally estimating the effect of YouTube’s recommender system using counterfactual bots Journal Article
In: PNAS, vol. 121, iss. 8, 2024.
Deplatforming did not decrease Parler users’ activity on fringe social media Journal Article
In: PNAS Nexus, vol. 2, iss. 3, 2023.
Quantifying partisan news diets in Web and TV audiences Journal Article
In: Science Advances, vol. 8, iss. 28, 2022.
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.
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.
Comparing Estimates of News Consumption from Survey and Passively Collected Behavioral Data Journal Article
In: Public Opinion Quarterly, 2021.
Examining the consumption of radical content on YouTube Journal Article
In: Proceedings of the National Academy of Sciences, vol. 118, no. 32, 2021.
Research note: Examining potential bias in large-scale censored data Journal Article
In: Harvard Kennedy School (HKS) Misinformation Review, 2021.
Measuring the news and its impact on democracy Journal Article
In: Proceedings of the National Academy of Sciences, vol. 118, no. 15, 2021.
Evaluating the fake news problem at the scale of the information ecosystem Journal Article
In: Science Advances, vol. 6, no. 14, pp. eaay3539, 2020.
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.
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.
The science of fake news Journal Article
In: Science, vol. 359, no. 6380, pp. 1094-1096, 2018.
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.




