Computational Social Science Forum — Outercity Policing: Drivers of Police Spending in a Changing Metropolis

CSS Training Program

March 8, 2021
12:00pm to 1:30pm
Virtual Participation


Computational Social Science Forum
Date: Monday, March 8, 2021
Time: 12:00-1:30 PM Pacific Time
Location: Register to receive the schedule and access links.

Strong ties and network search

Speaker: Mathijs De Vaan, Assistant Professor, Berkeley Haas School of Business
Abstract: While social networks research has carefully documented the consequences of strong ties on information exchange, much less is known about the effects of strong ties on engaging in network search. In this paper, we ask whether strong ties between network partners prevent them from searching for and potentially switching to alternative network partners and we address this question by examining the referral network between physicians. Strong referral relationships between physicians have been argued to improve coordination in health care, potentially leading to better health outcomes. But strong referral relationships may also lead to lock in and prevent physicians from considering alternative referral options. We leverage the implementation of a novel strategy introduced by health insurers in an attempt to curb the ever-growing spending on health care in the United States. Recognizing that the incentives for physicians to consider spending when selecting referral partners are lacking, health insurance companies started negotiating Global Budget Capitation (GBC) contracts to providers. These contracts include a fixed budget for a provider and incentivizes the provider to become more sensitive to spending by allowing them to keep savings if spending is below budget and force them to contribute when spending exceeds the budget. Importantly, spending by referral partners is credited against the budget. Using a difference-in-differences regression framework, we examine whether the introduction of GBC contracts shift referral patterns of physicians and we evaluate whether the treatment effect is moderated by the strength of the referral tie between two physicians. Results suggest that physicians indeed shift their referral patterns to partners with lower average spending, but that this treatment effect is substantially lower when two physicians have a strong referral relationship. We find no significant changes in the health outcomes of patients treated by physicians shifting their referral patterns suggesting that there are no short term adverse health effects of rebuilding referral relationships. We conclude by estimating the savings in spending that are not realized as a consequence of the maintenance of strong referral ties.

The Computational Social Science Forum is an informal setting for the interdisciplinary exchange of ideas and scholarship at the intersection of social science and data science. Weekly meetings are hosted by researchers from BIDS and D-Lab, and participants engage in a variety of activities such as presentations of work in progress, discussions and critiques of recent papers, introductions to new tools and methods, discussions around ethics, fairness, inequality, and responsible conduct of research, as well as professional development. We welcome social scientists researchers with interests in data science methods and tools, and data scientists with applications or interests in public policy, social, behavioral, and health sciences. Participants include graduate students, postdocs, staff, and faculty, and members are encouraged to attend regularly in order to foster community around improving computational social science research, supporting the development and research of group members, and fostering new collaborations. This Forum is organized as part of the Computational Social Science Training Program, and interested UC Berkeley community members are invited to use this registration form to receive the schedule and access links. Please contact for more information.


Mathijs De Vaan

Assistant Professor, Berkeley Haas School of Business

Mathijs De Vaan is an Assistant Professor at the Haas School of Business. He earned his PhD from the Department of Sociology at Columbia University after defending his dissertation in June 2015. Mathijs’ main research agenda focuses on social networks in health care. Motivated by the high level of variation in the cost and quality of care, Mathijs’ research examines the role of relationships between patients, between physicians, and between patients and physicians in the emergence and persistence of this variation. A second line of inquiry focuses on inequality in the production of science.