NBER Working Papers by William Jack

Contact and additional information for this authorAll NBER papers and publicationsNBER Working Papers onlyInformation about this author at RePEc

Working Papers

September 2016Borrowing Requirements, Credit Access, and Adverse Selection: Evidence from Kenya
with Michael Kremer, Joost de Laat, Tavneet Suri: w22686
We examine the potential of asset-collateralized loans in low-income country credit markets. When a Kenyan dairy cooperative exogenously replaced high down payments and joint liability requirements with loans collateralized by the asset itself - a large water tank- loan take-up increased from 2.4% to 41.9%. In contrast, substituting joint liability requirements for deposit requirements had no impact on loan take up. There were no repossessions among farmers allowed to collateralize 75% of their loans, and a 0.7% repossession rate among those offered 96% asset collateralization. A Karlan-Zinman test based on waiving borrowing requirements ex post finds evidence of adverse selection with very low deposit requirements, but not of moral hazard. A simple model and rough calibration suggests tha...
September 2012State vs Consumer Regulation: An Evaluation of Two Road Safety Interventions in Kenya
with James Habyarimana: w18378
This paper compares the relative impact of two road safety interventions in the Kenyan minibus or matatu sector: a top down set of regulatory requirements known as the Michuki Rules and a consumer empowerment intervention. We use very detailed insurance claims data on three classes of vehicles to implement a difference-in-differences estimation strategy to measure the impact of the Michuki Rules. Despite strong political leadership and dedicated resources, we find no statistically significant effect of the Michuki Rules on accident rates. In contrast, the consumer empowerment intervention that didn't rely on third party enforcement has very large and significant effects on accident rates. Our intent-to-treat estimates suggest reductions in accident rates of at least 50%. Our analysis sugg...

Published: State versus Consumer Regulation: An Evaluation of Two Road Safety Interventions in Kenya, James Habyarimana, William Jack. in African Successes, Volume I: Government and Institutions, Edwards, Johnson, and Weil. 2016

January 2011Mobile Money: The Economics of M-PESA
with Tavneet Suri: w16721
Mobile money is a tool that allows individuals to make financial transactions using cell phone technology. In this paper, we report initial results of two rounds of a large survey of households in Kenya, the country that has seen perhaps the most rapid and widespread growth of a mobile money product - known locally as M‐PESA - in the developing world. We first summarize the mechanics of M-PESA, and review its potential economic impacts. We then document the sequencing of adoption across households according to income and wealth, location, gender, and other socio‐economic characteristics, as well as the purposes for which the technology is used, including saving, sending and receiving remittances, and direct purchases of goods and services. In addition, we report findings from a survey of M...
May 2005Employee Cost-Sharing and the Welfare Effects of Flexible Spending Accounts
with Arik Levinson, Sjamsu Rahardja: w11315
Flexible Spending Accounts (FSAs) subsidize out-of-pocket health expenses not covered by employer-provided health insurance, making health care cheaper ex post, but also reducing the incentive to insure. We use a cross section of .rm-level data to show that FSAs are indeed associated with reduced insurance coverage, and to evaluate the welfare consequences of this shift. Correcting for selection effects we find that FSAs are associated with insurance contracts that have coinsurance rates about 7 percentage points higher, relative to a sample average coinsurance rate of 17 percent. Meanwhile, coinsurance rates net of the subsidy are approximately unchanged, providing evidence that FSAs are welfare-neutral. These results show that FSAs may explain a significant fraction of the shift in heal...

Published: Jack, William & Levinson, Arik & Rahardja, Sjamsu, 2006. "Employee cost-sharing and the welfare effects of flexible spending accounts," Journal of Public Economics, Elsevier, vol. 90(12), pages 2285-2301, December. citation courtesy of

Contact and additional information for this authorAll NBER papers and publicationsNBER Working Papers onlyInformation about this author at RePEc

NBER Videos

National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email:

Contact Us