|Position:||Assistant Professor, The Information School|
Adjunct Assistant Professor, Computer Science & Engineering
Director, Data Science and Analytics Lab
University of Washington
|Contact:||joshblum[@]uw[.]edu / +1 (206) 685-8746
for encrypted correspondence: my public key
|My work focuses on the economic and social impacts of new technologies, and the development of new methods for the quantitative analysis of massive, spatio-temporal network data. Most of this work is based in developing and conflict-affected countries. I have open research positions for qualified PhD students.|
|Note: I am currently hiring a full- or part-time data scientist / software engineer. [apply here]|
News and updates
- 12/2013: I am hiring a full- or part-time data scientist / software engineer. [apply here]
- 12/2013: Upcoming presentations: at ACM-DEV and at ICTD in Cape Town, South Africa
- 10/2013: Google Research Award to study networks in Afghanistan. Thanks Google!
- 09/2013: Early Career Faculty Award: Thanks to Intel for the generous gift!
- show more...
Charity and Reciprocity in Mobile Phone-Based Giving in the Aftermath of Natural Disasters - joint with Marcel Fafchamps (Oxford) and Nathan Eagle (Santa Fe Institute)
We provide empirical evidence that an early form of "mobile money" is used to share risk. Our analysis uses a unique dataset containing the entire universe of one country's mobile phone communications over a four-year period, and exploits spatio-temporal variation in communication caused by earthquakes and floods. We show that individuals are significantly more likely to send money to people affected by economic shocks, and use these shock-induced transfers to test between two models of phone-based giving. The data indicate that gifts are driven more by a desire for reciprocity than purely altruistic motives. [View Video]
Understanding the causes and effects of internal migration is critical to the effective design and implementation of policies that promote human development. Here, we describe how large sources of geotagged data generated by mobile phones can provide a novel source of data on internal migration. We develop and formalize the concept of inferred mobility, and compute this and other metrics on a large dataset containing the phone records of 1.5 million Rwandans over four years. Our empirical results corroborate the findings of a recent government survey that notes relatively low levels of permanent migration in Rwanda. [View Video]
Expanding Rural Cellular Networks with Virtual Coverage - joint with Kurtis Heimerl, Kashif Ali, Brian Gawalt, and Eric Brewer
We present an alternative system for implementing large-scale rural cellular networks. Rather than providing constant coverage, we instead provide virtual coverage: coverage that is only present when requested. Virtual coverage powers the network on demand, which reduces overall power draw, lowers the cost of rural connectivity, and enables new markets.
Divided We Call: Disparities in Access and Use of Mobile Phones in Rwanda - joint with Nathan Eagle (Santa Fe Institute)
This paper provides quantitative evidence of disparities in mobile phone access and use in Rwanda. Our analysis leverages data collected in 2,200 field interviews, which was merged with terabytes of transaction-level call histories obtained from the mobile telecommunications operator.
In the Field and Ongoing Projects
Violence and Precautionary Savings: Experimental Evidence from Mobile Phone-Based Salaries in Afghanistan - joint with Michael Callen (UCLA) and Tarek Ghani (UC Berkeley)
Private firms in conflict-affected countries face insecurity, corruption, poor infrastructure, and weak property rights. Disbursing employee wages is a challenge as cash-based payment systems are vulnerable to indirect costs in the form of leakage and theft. We implement a randomized field experiment in Afghanistan to test the effects of a mobile phone-based salary payment system on performance outcomes in a private firm with approximately 400 employees.
Freedom to Speak: How a Free Calling Network Affects Community Health Worker Knowledge and Productivity
We study the extent to which increased peer communication can improve the effectiveness of community health workers in Tanzania. Through a large field experiment in which roughly 8,000 health workers receive staggered access to a free mobile phone network, we measure the impact of this intervention on actual patterns of interaction and on health and welfare outcomes of workers and patients.
Savings in Conflict: The Impact of a Mobile Phone-Based Defined-Contribution Plan in Afghanistan - joint with Michael Callen (UCLA) and Tarek Ghani (UC Berkeley)
We study the extent to which a mobile phone-based defined contribution savings account can improve the financial capabilities and welfare outcomes of salaried employees at a large Afghan firm. Our research design uses a randomized controlled trial to understand whether a defined-contribution savings product can create an enduring increase in savings.
A Society of Silent Separation: The Impact of Migration on Ethnic Segregation in Estonia - joint with Ott Toomet (Tartu University)
We exploit a novel source of data to model the impact of migration and urbanization on segregation in Estonia. Analyzing the complete mobile phone records of hundreds of thousands of Estonians, we find that the ethnic composition of an individual's geographic neighborhood heavily influences the structure of the individual's phone-based network. We further find that patterns of segregation are significantly different for migrants than for the at-large population: migrants are more likely to interact with coethnics than non-migrants, but are less sensitive to the ethnic composition of their immediate neighborhood than non-migrants.