Research

Social distancing is the core policy response to coronavirus disease 2019 (COVID-19). But, as federal, state and local governments begin opening businesses and relaxing shelter-in-place orders worldwide, we lack quantitative evidence on how policies in one region affect mobility and social distancing in other regions and the consequences of uncoordinated regional policies adopted in the presence of such spillovers. To investigate this concern, we combined daily, county-level data on shelter-in-place policies with movement data from over 27 million mobile devices, social network connections among over 220 million Facebook users, daily temperature and precipitation data from 62,000 weather stations, and county-level census data on population demographics to estimate the geographic and social network spillovers created by regional policies across the United States. ...

Decision-making on networks can be explained by both homophily and social influence. While homophily drives the formation of communities with similar characteristics, social influence occurs both within and between communities. Social influence can be reasoned through role theory, which indicates that the influences among individuals depend on their roles and the behavior of interest. To operationalize these social science theories, we empirically identify the homophilous communities and use the community structures to capture the “roles”, which affect the particular decision-making processes. ...

Taxation of firms is a complicated matter that often lacks transparency and stirs controversy. We aim to address the inconsistencies and lack of transparency in taxation policies, monopolization, market centralization, and biases against startup firms in economic systems. Digital firms get taxed disproportionately less than their physical counterparts: a prime example of this is Amazon. Relative to its size, Amazon pays about 1% of the tax that Walmart pays. We introduce a radically different approach to taxation by taxing a firm based on its direct and indirect impact on the economy. ...

Understanding drivers of behaviors can help us build better predictive models. Much debate has been dedicated to how social influence permeates through social networks. While on the one hand, social influence is thought to be localized within communities, other work has demonstrated that social influence can diffuse through weak ties within networks. In focusing on how social influence flows through direct ties, however, the literature has missed the broader potential of leveraging social groups, which also exert social influence on their members. ...