David Lazer
Other
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Other InterestsScience, Social Networks, Regulation and Governance, EPJ Data Science
Publications
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More Voices Than Ever? Quantifying Media Bias in Networks
11/2011;
Social media, such as blogs, are often seen as democratic entities that allow more voices to be heard than the conventional mass or elite media. Some also feel that social media exhibits a balancing force against the arguably slanted elite media. A systematic comparison between social and mainstream... [more] Social media, such as blogs, are often seen as democratic entities that allow more voices to be heard than the conventional mass or elite media. Some also feel that social media exhibits a balancing force against the arguably slanted elite media. A systematic comparison between social and mainstream media is necessary but challenging due to the scale and dynamic nature of modern communication. Here we propose empirical measures to quantify the extent and dynamics of social (blog) and mainstream (news) media bias. We focus on a particular form of bias---coverage quantity---as applied to stories about the 111th US Congress. We compare observed coverage of Members of Congress against a null model of unbiased coverage, testing for biases with respect to political party, popular front runners, regions of the country, and more. Our measures suggest distinct characteristics in news and blog media. A simple generative model, in agreement with data, reveals differences in the process of coverage selection between the two media.
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Social sensing for epidemiological behavior change.
UbiComp 2010: Ubiquitous Computing, 12th International Conference, UbiComp 2010, Copenhagen, Denmark, September 26-29, 2010, Proceedings; 01/2010
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Social sensing: obesity, unhealthy eating and exercise in face-to-face networks.
Proceedings of Wireless Health 2010, WH 2010, San Diego, CA, USA, October 5-7, 2010; 01/2010
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9.43Impact points
Inferring friendship network structure by using mobile phone data.
Proceedings of the National Academy of Sciences of the United States of America. 09/2009;
Data collected from mobile phones have the potential to provide insight into the relational dynamics of individuals. This paper compares observational data from mobile phones with standard self-report survey data. We find that the information from these two data sources is overlapping but distinct. ... [more] Data collected from mobile phones have the potential to provide insight into the relational dynamics of individuals. This paper compares observational data from mobile phones with standard self-report survey data. We find that the information from these two data sources is overlapping but distinct. For example, self-reports of physical proximity deviate from mobile phone records depending on the recency and salience of the interactions. We also demonstrate that it is possible to accurately infer 95% of friendships based on the observational data alone, where friend dyads demonstrate distinctive temporal and spatial patterns in their physical proximity and calling patterns. These behavioral patterns, in turn, allow the prediction of individual-level outcomes such as job satisfaction.
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29.75Impact points
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Using reality mining to improve public health and medicine.
Studies in health technology and informatics. 02/2009; 149:93-102.
We live our lives in digital networks. We wake up in the morning, check our e-mail, make a quick phone call, commute to work, buy lunch. Many of these transactions leave digital breadcrumbs - tiny records of our daily experiences. Reality mining, which pulls together these crumbs using statistical a... [more] We live our lives in digital networks. We wake up in the morning, check our e-mail, make a quick phone call, commute to work, buy lunch. Many of these transactions leave digital breadcrumbs - tiny records of our daily experiences. Reality mining, which pulls together these crumbs using statistical analysis and machine learning methods, offers an increasingly comprehensive picture of our lives, both individually and collectively, with the potential of transforming our understanding of ourselves, our organizations, and our society in a fashion that was barely conceivable just a few years ago. It is for this reason that reality mining was recently identified by Technology Review as one of "10 emerging technologies that could change the world" [1]. Many everyday devices provide the raw database upon which reality mining builds; sensors in mobile phones, cars, security cameras, RFID ('smart card') readers, and others, all allow for the measurement of human physical and social activity. Computational models based on such data have the potential to dramatically transform the arenas of both individual and community health. Reality mining can provide new opportunities with respect to diagnosis, patient and treatment monitoring, health services planning, surveillance of disease and risk factors, and public health investigation and disease control. Currently, the single most important source of reality mining data is the ubiquitous mobile phone. Every time a person uses a mobile phone, a few bits of information are left behind. The phone pings the nearest mobile-phone towers, revealing its location. The mobile phone service provider records the duration of the call and the number dialed. In the near future, mobile phones and other technologies will collect even more information about their users, recording everything from their physical activity to their conversational cadences. While such data pose a potential threat to individual privacy, they also offer great potential value both to individuals and communities. With the aid of data-mining algorithms, these data could shed light on individual patterns of behavior and even on the well-being of communities, creating new ways to improve public health and medicine. To illustrate, consider two examples of how reality mining may benefit individual health care. By taking advantage of special sensors in mobile phones, such as the microphone or the accelerometers built into newer devices such as Apple's iPhone, important diagnostic data can be captured. Clinical pilot data demonstrate that it may be possible to diagnose depression from the way a person talks - a depressed person tends to speak more slowly, a change that speech analysis software on a phone might recognize more readily than friends or family do. Similarly, monitoring a phone's motion sensors can also reveal small changes in gait, which could be an early indicator of ailments such as Parkinson's disease. Within the next few years reality mining will become more common, thanks in part to the proliferation and increasing sophistication of mobile phones. Many handheld devices now have the processing power of low-end desktop computers, and they can also collect more varied data, due to components such as GPS chips that track location. The Chief Technology Officer of EMC, a large digital storage company, estimates that this sort of personal sensor data will balloon from 10% of all stored information to 90% within the next decade. While the promise of reality mining is great, the idea of collecting so much personal information naturally raises many questions about privacy. It is crucial that behavior-logging technology not be forced on anyone. But legal statutes are lagging behind data collection capabilities, making it particularly important to begin discussing how the technology will and should be used. Therefore, an additional focus of this chapter will be the development of a legal and ethical framework concerning the data used by reality mining techniques.
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Networks, Hierarchies, and Markets: Aggregating Collective Problem Solving in Social Systems
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2009;
How do decentralized systems collectively solve problems? Here we explore the interplay among three canonical forms of collective organization--markets, networks, and hierarchies--in aggregating decentralized problem solving. We examine these constructs in the context of how the offices of members o... [more] How do decentralized systems collectively solve problems? Here we explore the interplay among three canonical forms of collective organization--markets, networks, and hierarchies--in aggregating decentralized problem solving. We examine these constructs in the context of how the offices of members of Congress individually and collectively wrestle with the Internet, and, in particular, their use of official websites. Each office is simultaneously making decisions about how to utilize their website. These decisions are only partially independent, where offices are looking at each other for lessons, following the same directives from above about what to do with the websites, and confront the same array of potential vendors to produce their website. Here we present the initial results from interviews with 99 Congressional offices and related survey of 100 offices about their decisions regarding how to use official Member websites. Strikingly, we find that there are relatively few efforts by offices to evaluate what constituents want or like on their websites. Further, we find that diffusion occurs at the "tip of the iceberg": offices often look at each others' websites (which are publicly visible), but rarely talk to each other about their experiences or how they manage what is on their websites (which are not publicly visible). We also find that there are important market drivers of what is on websites, with the emergence of a small industry of companies seeking to serve the 440 Members. Hierarchical influences--through the House and through the party conferences--also constrain and subsidize certain practices.
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Who Wants to Deliberate--And Why?
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2009;
Interest in deliberative theories of democracy has grown tremendously among political theorists over the last twenty years. Many scholars in political behavior, however, are skeptical that it is a practically viable theory, even on its own terms. They argue (inter alia) that most people dislike poli... [more] Interest in deliberative theories of democracy has grown tremendously among political theorists over the last twenty years. Many scholars in political behavior, however, are skeptical that it is a practically viable theory, even on its own terms. They argue (inter alia) that most people dislike politics, and that deliberative initiatives would amount to a paternalistic imposition. Using two large, representative samples investigating people's hypothetical willingness to deliberate and their actual behavior in response to a real invitation to deliberate with their member of Congress, we find: 1) that willingness to deliberate in the U.S. is much more widespread than expected; and 2) that it is precisely people who are less likely to participate in traditional partisan politics who are most interested in deliberative participation. They are attracted to such participation as a partial alternative to "politics as usual."
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Lending a Helping Hand: Voluntary Engagement in Knowledge Sharing
11/2008;
Knowledge is essential for the functioning of every social system, especially for professionals in knowledge-intensive organizations. Since individuals do not possess all the work-related knowledge that they require, they turn to others in search for that knowledge. While prior research has mainly f... [more] Knowledge is essential for the functioning of every social system, especially for professionals in knowledge-intensive organizations. Since individuals do not possess all the work-related knowledge that they require, they turn to others in search for that knowledge. While prior research has mainly focused on antecedents and consequences of knowledge sharing and understanding why people do not share knowledge, less is known why people provide knowledge, and what conditions trigger voluntary engagement in knowledge sharing. Our paper addresses this gap by proposing a multi-level framework for voluntary engagement in knowledge sharing: individual, relational, group, and informational. We provide illustrations from a particular knowledge-intensive community, DNA forensic scientists who work at public laboratories.
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A New Order of Things: Managing Novelty and Cooperation on E-Government Projects
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2008;
In this paper, we explore the challenges of managing e-government projects. In particular, we highlight two extraordinary managerial challenges that e-government poses: novelty and cross-agency cooperation. E-government is novel because it offers some fundamentally new possibilities for how governme... [more] In this paper, we explore the challenges of managing e-government projects. In particular, we highlight two extraordinary managerial challenges that e-government poses: novelty and cross-agency cooperation. E-government is novel because it offers some fundamentally new possibilities for how government does business. The management of e-government is, in significant part, the management of ideas, creativity, and knowledge. E-government requires cross-agency cooperation because of functional needs for scale, consistency, and integration. We examine how four governments that have adopted a project-based approach to the introduction of e-government have coped with the challenges of novelty and cross-agency collaboration. Our findings indicate that e-government projects experience different activities and coordination mechanisms according to the stage of completion of the project and the complexity of the task at hand. We discuss the implications of our findings for the management of e-government projects.
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Networks and Political Attitudes: Structure, Influence, and Co-evolution
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2008;
How do political views and social affiliations co-evolve? A long stream of research has focused on the relationship between political views and social affiliations, however, it is typically difficult to discern the causal relationship between views and affiliations. Here we use longitudinal attitudi... [more] How do political views and social affiliations co-evolve? A long stream of research has focused on the relationship between political views and social affiliations, however, it is typically difficult to discern the causal relationship between views and affiliations. Here we use longitudinal attitudinal and whole network data collected at critical times (notably, at the inception of the system) to pinpoint and specify the determinants of attitudes and affiliations. We find significant conformity tendencies: individuals shift their political views toward the political views of their associates. This conformity is driven by social ties rather than task ties. We also find that, while individuals tend to associate with similar others, political views are notably less a basis for associational choices than demographic and institutional factors.
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Searching for Answers: Networks of Practice among Public Administrators
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2008;
The obstacles to innovation in government have been the subject of much academic scrutiny. Far less studied, however, has been the sharing of innovation among public administrators. How does a lesson learned, for example, in one agency provide insights that other agencies might borrow? Such sharing ... [more] The obstacles to innovation in government have been the subject of much academic scrutiny. Far less studied, however, has been the sharing of innovation among public administrators. How does a lesson learned, for example, in one agency provide insights that other agencies might borrow? Such sharing of experiences across agency boundaries, while at times potentially offering enormous value to the system as a whole, faces substantial challenges. In the US, one fundamental challenge is the natural dispersion of government across the country, within state and local government. We examine the alternative mechanisms that evolve within the public sector to compensate for this dispersion of expertise. In particular, we argue that the knowledge sharing practices of DNA forensic scientists working in government crime labs constitute such an alternative mechanism. Findings from an in-depth case study of this community suggest that concerns around trust, reliability, and cost, interacting with context specific features, result in the emergence of a network of practice that is fairly parochial, with a few dominant hubs, and a reliance on different channels depending on the needs for security in communication. We conclude by discussing the theoretical and practical implications of our findings.
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9.43Impact points
Structure and tie strengths in mobile communication networks.
Proceedings of the National Academy of Sciences of the United States of America. 06/2007; 104(18):7332-6.
Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing u... [more] Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties but fall apart after a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities and find that, when it comes to information diffusion, weak and strong ties are both simultaneously ineffective.
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Members of congress websites: diffusion at the tip of the iceberg.
Proceedings of the 8th Annual International Conference on Digital Government Research, Bridging Disciplines & Domains, DG.O 2007, Philadelphia, Pennsylvania, USA, May 20-23, 2007; 01/2007
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Connecting to congress: improving deliberation in the information age.
Proceedings of the 8th Annual International Conference on Digital Government Research, Bridging Disciplines & Domains, DG.O 2007, Philadelphia, Pennsylvania, USA, May 20-23, 2007; 01/2007
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29.75Impact points
Human genetics. Finding criminals through DNA of their relatives.
Science (New York, N.Y.). 07/2006; 312(5778):1315-6.
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1.43Impact points
Statutory frameworks for regulating information flows: drawing lessons for the DNA data banks from other government data systems.
The Journal of law, medicine & ethics : a journal of the American Society of Law, Medicine & Ethics. 02/2006; 34(2):366-74.
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Technology adoption and institutional change in the United States senate: an analysis of web site content.
Proceedings of the 7th Annual International Conference on Digital Government Research, DG.O 2006, San Diego, California, USA, May 21-24, 2006; 01/2006
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Connecting to Congress.
Proceedings of the 7th Annual International Conference on Digital Government Research, DG.O 2006, San Diego, California, USA, May 21-24, 2006; 01/2006
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The Parable of the Hare and the Tortoise: Small Worlds, Diversity, and System Performance
Harvard University, John F. Kennedy School of Government, Working Paper Series. 01/2005;
This paper shows that increases in the minimum wage rate can have ambiguous effects on the working hours and welfare of employed workers in competitive labor markets. The reason is that employers may not comply with the minimum wage legislation and instead pay a lower subminimum wage rate. If worker... [more] This paper shows that increases in the minimum wage rate can have ambiguous effects on the working hours and welfare of employed workers in competitive labor markets. The reason is that employers may not comply with the minimum wage legislation and instead pay a lower subminimum wage rate. If workers are risk neutral, we prove that working hours and welfare are invariant to the minimum wage rate. If workers are risk averse and imprudent (which is the empirically likely case), then working hours decrease with the minimum wage rate, while their welfare may increase.
Following (4)
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Ines Anja Mergel
Syracuse University -
James Fowler
University of California at San Diego -
Jukka-Pekka Onnela
Harvard University
