James Hammitt

Professor of Economics and Decision Sciences
Health Policy and Management
Harvard School of Public Health
(617) 432-4343
Home page:

James K. Hammitt, Ph.D., is Professor of Economics and Decision Sciences in the Departments of Health Policy and Management and of Environmental Health and Director of the Harvard Center for Risk Analysis. Professor Hammitt's research focuses on the development and application of quantitative methods - including benefit-cost, decision, and risk analysis - to health and environmental policy. Topics include management of long-term environmental issues with major scientific uncertainties, such as global climate change and stratospheric-ozone depletion, evaluation of ancillary benefits and countervailing risks associated with risk-control measures, and characterization of social preferences over health and environmental risks using revealed-preference, contingent-valuation, and health-utility methods. Dr. Hammitt earned his A.B. and Sc.M. in Applied Mathematics in 1978, his M.P.P., in 1981, and his Ph.D. in Public Policy in 1988, all from Harvard University. He has been appointed Senior Mathematician at the RAND Corporation (Santa Monica, California) and to the Pierre-de-Fermat Chaire d’Éxcellence at the Toulouse School of Economics (France).

Posted on March 31, 2013
Journal of Benefit-Cost Analysis 2013 4(1): 107-30

Many public policies and private actions affect the risk of injury, illness, or death, yet changes in these risks are not easily valued using market prices. We discuss how to value these risk reductions in the context of benefit-cost analysis. We ... (more »)

Posted on March 2, 2012
Authors: Neumann PJ, Cohen JT, Hammitt JK, Concannon TW, Auerbach HR, Fang C, Kent DM
Health Econ. 2012 21(3): 238-51  DOI: 10.1002/hec.1704

We assessed how much, if anything, people would pay for a laboratory test that predicted their future disease status. A questionnaire was administered via an internet-based survey to a random sample of adult US respondents. Each respondent answ... (more »)

Posted on November 27, 2012
Environ Sci Technol 2012 46(22): 12337-46  DOI: 10.1021/es302652m

Fish consumption advisories instruct vulnerable consumers to avoid high mercury fish and to limit total fish intake to reduce neurotoxic risk. Consumption data from the U.S. suggest that nontarget consumers also respond to such advice. These consu... (more »)

Posted on February 4, 2013
Authors: Hogan DR, Salomon J, Canning D, Hammitt JK, Zaslavsky AM, Bärnighausen T
Sex Transm Infect 2012 88Suppl 2:i17-23  DOI: 10.1136/sextrans-2012-050636


Population-based HIV testing surveys have become central to deriving estimates of national HIV prevalence in sub-Saharan Africa. However, limited participation in these surveys can lead to selection bias. We control for selectio... (more »)

Posted on February 8, 2011
Authors: Tsou MW, Liu JT, Hammitt JK
Biology Letters 2011  PubmedID: 21288936   DOI: 10.1098/rsbl.2010.1208

Using contemporary population data from Taiwan, we examine the relationships between parental age difference, educationally assortative mating, income and offspring count. Controlling for women's reproductive value (measured by age at first bir... (more »)

Posted on April 15, 2011
Authors: Haninger K, Hammitt JK
Risk Analysis 2011  PubmedID: 21488924   DOI: 10.1111/j.1539-6924.2011.01617.x.

We design and conduct a stated-preference survey to estimate willingness to pay (WTP) to reduce foodborne risk of acute illness and to test whether WTP is proportional to the corresponding gain in expected quality-adjusted life years (QALYs). I... (more »)

Posted on August 15, 2011
Author: Hammitt JK
Health Econ 2011  PubmedID: 21834025   DOI: 10.1002/hec.1782

Nord (2011) criticizes standard arguments which assert that consistency requires that future health benefits must be discounted at the same rate as future costs in cost-effectiveness analysis (CEA). He suggests these arguments are misguided bec... (more »)

Posted on August 16, 2011
Risk Anal. 2011  PubmedID: 21838730   DOI: 10.1111/j.1539-6924.2011.01661.x.

Behavioral economics has captured the interest of scholars and the general public by demonstrating ways in which individuals make decisions that appear irrational. While increasing attention is being focused on the implications of this research... (more »)

Posted on October 24, 2011
Journal of Benefit-Cost Analysis 2011 2(2)  DOI: 10.2202/2152-2812.1059

As traditionally conducted, benefit-cost analysis is rooted in neoclassical welfare economics, which, in its most simplified form, assumes that individuals act rationally and are primarily motivated by self-interest, making decisions that maxim... (more »)

Posted on October 24, 2011
Authors: Tsai WJ, Liu JT, Hammitt JK
Environ Resource Econ 2011 49425-443  DOI: 10.1007//s10640-010-9440-z

This study uses a unique longitudinally-linked employer–employee dataset to estimate the magnitude of bias in estimating the value per statistical life (VSL) that arises from the conventional use of industry-average occupationa... (more »)

Posted on October 24, 2011
Authors: Chahine T, Schultz B, Zartarian V, Subramanian SV, Spengler J, Hammitt JK, Levy JI
Jounral of Exposure Science and Environmental Epidemiology 2011 21(6)  PubmedID: 2140727

Despite substantial attention toward environmental tobacco smoke (ETS) exposure, previous studies have not provided adequate information to apply broadly within community-scale risk assessments. We aim to estimate residential concentrations of ... (more »)

Posted on January 20, 2013
Authors: Cropper M, Hammitt JK, Robinson LA
Annual Review of Resource Economics 2011 3313-336  DOI: 10.1146/annurev.resource.012809.103949

The value of mortality risk reduction is an important component of the benefits of environmental policies. In recent years, the number, scope, and quality of valuation studies have increased dramatically. Revealed-preference studies of wage compen... (more »)

Posted on January 20, 2013
Journal of Benefit-Cost Analysis 2011 2(1)  DOI: 10.2202/2152-2812.1009

The income elasticity of the value per statistical life (VSL) is an important parameter for policy analysis. Mortality risk reductions often dominate the quantified benefits of environmental and other policies, and estimates of their value are fre... (more »)

Posted on April 1, 2010
Authors: Lee GM, Salomon J, Gay C, Hammitt JK
Health Qual Life Outcomes 2010 8(28)  PubmedID: 20226042   DOI: 10.1186/1477-7525-8-28

BACKGROUND: A 26-valent Group A Streptococcus (GAS) vaccine candidate has been developed that may provide protection against pharyngitis, invasive disease and rheumatic fever. However, recommendations for the use of a new vaccine must be inform... (more »)

Posted on June 15, 2010
Authors: Rice GE, Hammitt JK, Evans JS
Environmental Science and Technology 2010  PubmedID: 20540573   DOI: 10.1021/es903359u

We developed a probabilistic model to characterize the plausible distribution of health and economic benefits that would accrue to the U.S. population following reduction of methyl mercury (MeHg) exposure. MeHg, a known human developmental neur... (more »)

James Hammitt
An advanced course that introduces the standard model of decision-making under uncertainty and its conceptual foundations, as well as challenges, alternatives, and methodological issues arising from the application of these techniques to health issues. [Not offered in 2011-2012]

Benefits and Risks of Dietary Fish Consumption

Developing models to clarify tradeoffs among risks

Discount rates for the long run

Reviewing key issues relating to the discount rate

Methods for Research-Synthesis: A Cross-Disciplinary Approach Conference

A focus on alternative methods for synthesizing information when forecasting the effects of a policy

Preferences for Mortality Risk Reduction Over the Lifecycle

Investigating individuals' preferences for alternative interventions yielding the same increase in life expectancy

Risk, Perception, and Response Conference

Increasing our understanding of the situations in which people are likely to react poorly to evidence of risk

Using Social-Welfare Functions to Evaluate Policies that Reduce Mortality Risk

Investigating alternative approaches to valuing risk reductions

Valuing Reductions in Morbidity Risk: WTP and QALYs

Investigating the relationship between WTP and QALYs and the differences in their theoretical foundations