Stanford University

HIV/AIDS

Estimating Probit Models with Self-Selected Treatments

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Outcomes research often requires estimating the impact of a binary treatment on a binary outcome in a non-randomized setting, such as the effect of taking a drug on mortality. The data often come from self-selected samples, leading to a spurious correlation between the treatment and outcome when standard binary dependent variable techniques, like logit or probit, are used. Intuition suggests that a two-step procedure (analogous to two-stage least squares) might be sufficient to deal with this problem if variables are available that are correlated with the treatment choice but not the outcome.

This paper demonstrates the limitations of such a two-step procedure. We show that such estimators will not generally be consistent. We conduct a Monte Carlo exercise to compare the performance of the two-step probit estimator, the two-stage least squares linear probability model estimator, and the multivariate probit. The results from this exercise argue in favour of using the multivariate probit rather than the two-step or linear probability model estimators, especially when there is more than one treatment, when the average probability of the dependent variable is close to 0 or 1, or when the data generating process is not normal. We demonstrate how these different methods perform in an empirical example examining the effect of private and public insurance coverage on the mortality of HIV+ patients.

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Journal Articles
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Statistics in Medicine
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More Than Humanitarianism: A Strategic U.S. Approach Toward Africa

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Lyman and Morrison will discuss the Council on Foreign Relations-sponsored Independent Task Force Report on the US and Africa. The Report argues that Africa is becoming steadily more central to the United States and to the rest of the world in ways that transcend humanitarian interests. Africa now plays an increasingly significant role in supplying energy, preventing the spread of terrorism, and halting the devastation of HIV/AIDS. Africa's growing importance is reflected in the intensifying competition with China and other countries for both access to African resources and influence in this region. A more comprehensive U.S. policy toward Africa is needed, the report states, and it lays out recommendations for policymakers to craft that policy. The report is available at www.cfr.org.

Princeton N. Lyman is the Ralph Bunche Senior Fellow and Director for Africa Policy Studies at the Council on Foreign Relations. He is also an Adjunct Professor at Georgetown University. Ambassador Lyman served for over three decades at the U.S. Department of State and the U.S. Agency for International Development (USAID), completing his government service as Assistant Secretary of State for International Organization Affairs. He was previously Ambassador to South Africa, Ambassador to Nigeria, Director of Refugee Programs and Director of the USAID Mission to Ethiopia.

From 1999 to 2000, he was Senior Fellow at the United States Institute of Peace. Ambassador Lyman held the position of Executive Director of the Global Interdependence Initiative of the Aspen Institute (1999 to 2003) and has received the President's Distinguished Service Award and the Department of State Distinguished Honor Award. Ambassador Lyman has published on foreign policy, African affairs, economic development, HIV/AIDS, UN reform, and peacekeeping. He coauthored the Council on Foreign Relations Special Report entitled Giving Meaning to "Never Again": Seeking an Effective Response to the Crisis in Darfur and Beyond. His book, Partner to History: The U.S. Role in South Africa's Transition to Democracy, was published in 2002. He earned his B.A. from the University of California at Berkeley and his Ph.D. in Political Science from Harvard University. He serves as the Co-Director of the Council on Foreign Relations-sponsored Independent Task Force on Africa.

J. Stephen Morrison is Director of the Africa Program and the Task Force on HIV/AIDS at the Center for Strategic and International Studies (CSIS). He joined CSIS in January 2000 and in late 2001, launched the CSIS Task Force on HIV/AIDS. The task force is a multiyear project co-chaired by Senators Bill Frist (R-TN) and John Kerry (D-MA) and funded by the Gates Foundation and the Catherine Marron Foundation. Dr. Morrison co-chaired the reassessment of the U.S. approach to Sudan that laid the basis for the Bush administration push for a negotiated peace settlement, and in the summer of 2002 he organized an energy expert mission to the Sudan peace negotiations in Kenya.

From 1996 through early 2000, Dr. Morrison served on the Secretary of State's Policy Planning Staff, where he was responsible for African affairs and global foreign assistance issues. In that position, he led the State Department's initiative on illicit diamonds and chaired an interagency review of the U.S. government's crisis humanitarian programs. From 1993 to 1995, Dr. Morrison conceptualized and launched USAID's Office of Transition Initiatives; he served as the office's first Deputy Director and created post-conflict programs in Angola and Bosnia. From 1992 until mid-1993, Dr. Morrison was the Democracy and Governance Adviser to the U.S. embassies and USAID missions in Ethiopia and Eritrea. He serves as the Co-Director of the Council on Foreign Relations-sponsored Independent Task Force on Africa.

CISAC Conference Room

Princeton Lyman Ralph Bunche Senior Fellow and Director for Africa Policy Studies Keynote Speaker Council on Foreign Relations
J. Stephen Morrison Director of the Africa Program and Task Force on HIV/AIDS Keynote Speaker Center for Strategic and International Studies
Seminars

CESP senior fellows receive funding from the Presidential Fund to support the launch of the new program on Food Security and the Environment

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"Feeding the World in the 21st Century: Exploring the Connections Between Food Production, Health, Enviromental Resources and International Security," was one of eight projects to be be awarded.

Eight research projects led by multidisciplinary-faculty teams have jointly received $1.05 million in the first round of awards made by Stanford's new $3 million Presidential Fund for Innovation in International Studies.

Coit D. Blacker, director of the Freeman Spogli Institute for International Studies, said the fund is the first program launched by the university's International Initiative, which seeks to encourage collaborative, cross-disciplinary approaches to address the global challenges of pursuing peace and security, improving governance and advancing human well-being.

The multi-year projects, selected by the International Initiative's executive committee from 37 proposals, will bring together faculty from fields that traditionally do not collaborate to produce new courses, symposia, conferences and research papers. Blacker, who chairs the executive committee, said additional awards totaling about $2 million will be made in 2007 and 2008.

President John Hennessy said he supports the research projects. "The world does not come to us as neat disciplinary problems, but as complex interdisciplinary challenges," he said. "The collaborative proposals we have selected for this first round of funding offer great potential to help shed light on some of the most persistent and pressing political issues on the global agenda today."

Projects in the first round of funding include:

Governance under Authoritarian Rule. Stephen Haber and Beatriz Magaloni, political science; Ian Morris, classics, history; and Jennifer Trimble, classics. The researchers will examine the political economy of authoritarian systems and determine why some authoritarian governments are able to make the transition to democracy, stable growth and functioning institutions, while others prove predatory and unstable.

Addressing Institutional and Interest Conflicts: Project Governance Structures for Global Infrastructure Development. Raymond Levitt, civil and environmental engineering; Doug McAdam and W. Richard Scott, sociology. The project will analyze the challenges of creating efficient and effective public/private institutions for the provision of low-cost, distributed and durable infrastructure services in emerging economies.

Combating HIV/AIDS in Southern Africa: The Treatment Revolution and Its Impact on Health, Well-Being and Governance. David Katzenstein, infectious diseases; and Jeremy Weinstein, political science. Based on the 2005 Group of 8's commitment to put 10 million people infected with HIV/AIDS on treatment within five years, this project will research the impact of this treatment revolution on health, well-being and governance in sub-Saharan Africa.

Evaluating Institutional Responses to Market Liberalization: Why Latin America Was Left Behind. Judith Goldstein, political science; Avner Greif, economics; Steven Haber, political science; Herb Klein, history; H. Grant Miller, Freeman Spogli Institute (FSI)/medicine; and Barry Weingast, political science. The project will research the interaction between inequality and Latin American institutions in explaining the poor economic performance of countries in the region during the past two decades, examining why reforms such as trade liberalization have failed to yield expected results.

Feeding the World in the 21st Century: Exploring the Connections Between Food Production, Health, Environmental Resources and International Security. Rosamond L. Naylor, FSI/economics; Stephen J. Stedman, FSI/political science; Peter Vitousek, biological sciences; and Gary Schoolnik, medicine, microbiology and immunology. The group will launch a new research and teaching program, titled "Food Security and the Environment," with an initial priority on determining linkages between food security, health and international security, and globalization, agricultural trade and the environment.

The Political Economy of Cultural Diversity. James D. Fearon, political science; and Romain Wacziarg, Graduate School of Business. The researchers will assess the impact of ethnic, linguistic and religious diversity on economic growth, trade and capital flows, governance, development of democracy and political stability.

In addition, two grants to plan forthcoming research projects have received $25,000:

Global Health by Design. Geoffrey Gurtner, plastic and reconstructive surgery; David Kelley, mechanical engineering; Thomas Krummel, surgery; Julie Parsonnet, medicine, health research and policy; and Paul Yock, medicine, bioengineering. The group will design a project to examine how new technology can be used to develop effective, affordable and sustainable methods and devices to prevent disease in the world's poorest countries.

Ecological Sanitation in Rural Haiti: An Interdisciplinary Approach to Sanitation and Soil Fertility. Ralph Greco, surgery; and Rodolfo Dirzo, biological sciences. The researchers will develop a plan to test the efficacy of ecological sanitation in decreasing disease and enhancing soil fertility in rural Haiti.

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New Presidential Fund for Innovation in International Studies awards eight grants totaling $1.05 million

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Stanford, CA - The Office of the President and the Stanford International Initiative announced today that eight new interdisciplinary research grants totaling $1.05 million have been awarded to Stanford faculty. The grants are the first to be awarded from Stanford's new $3 million Presidential Fund for Innovation in International Studies (PFIIS), created to support interdisciplinary research and teaching on three overarching global challenges: pursuing peace and security, improving governance, and advancing human well-being.

"The world does not come to us as neat disciplinary problems, but as complex interdisciplinary challenges," said Stanford President John Hennessy. "The collaborative proposals we have selected for this first round of funding offer great potential to help shed light on some of the most persistent and pressing political issues on the global agenda today - issues acutely important to our common future," he stated.

The research projects qualifying for first round funding of $1.025 million are:

  • Governance under Authoritarian Rule. Stephen Haber and Beatriz Magaloni, Political Science. Ian Morris, Classics, History and Jennifer Trimble, Classics. Will examine the political economy of authoritarian systems and determine why some authoritarian governments are able to transition to democracy, stable growth and functioning institutions, while others prove predatory and unstable.
  • Addressing Institutional and Interest Conflicts: Project Governance Structures for Global Infrastructure Development. Raymond Levitt, Civil & Environmental Engineering, Doug McAdam and W. Richard Scott, Sociology. Will analyze the challenges of creating efficient and effective structures for the provision of low cost, distributed and durable infrastructure services in emerging economies.
  • Combating HIV/AIDS in Southern Africa: The Treatment Revolution and its Impact on Health, Well-Being and Governance. David Katzenstein, Infectious Diseases, and Jeremy Weinstein, Political Science. Based on the 2005 Group of 8 commitment to put 10 million people infected with HIV/AIDS on treatment within five years, will research the impact of this treatment revolution on health, well-being and governance in Sub-Saharan Africa.
  • Evaluating Institutional Responses to Market Liberalization: Why Latin America Was Left Behind. Judith Goldstein, Political Science, Avner Greif, Economics, Stephen Haber, Political Science, Herb Klein, History, H.Grant Miller, FSI/Medicine, and Barry Weingast, Political Science. Will research the interaction between inequality and Latin American institutions in explaining the poor economic performance of Latin American countries in the past two decades, examining why reforms such as trade liberalization have failed to yield expected results.
  • Feeding the World in the 21st Century: Exploring the Connections Between Food Production, Health, Environmental Resources, and International Security. Rosamond Naylor, FSI/Economics, Stephen Stedman, FSI/Political Science, Peter Vitousek, Biological Sciences, and Gary Schoolnik, Medicine, Microbiology & Immunology. Launches new research and teaching program on "Food Security and the Environment," with an initial priority on determining linkages between Food Security, Health and International Security, and Globalization, Agricultural Trade and the Environment.
  • The Political Economy of Cultural Diversity. James D. Fearon, Political Science, and Romain Wacziarg, Graduate School of Business. Will assess the impact of ethnic, linguistic and religious diversity on economic growth, trade and capital flows, governance, development of democracy and political stability.

Two planning grants were also awarded:

  • Global Health by Design. Geoffrey Gurtner, Plastic & Reconstructive Surgery, David Kelley, Mechanical Engineering, Thomas Krummel, Surgery, Julie Parsonnet, Medicine, Health Research & Policy, and Paul Yock, Medicine, Bioengineering. Will design a project to examine how new technology can be used to develop effective, affordable and sustainable methods and devices to prevent disease in the world's poorest countries.
  • Ecological Sanitation in Rural Haiti: An Interdisciplinary Approach to Sanitation & Soil Fertility. Ralph Greco, Surgery, and Rodolfo Dirzo, Biological Sciences. Will develop a plan to test the efficacy of ecological sanitation in decreasing disease and enhancing soil fertility in rural Haiti.

"Addressing some of the most significant problems of our day, in the fields of security, governance and human well-being, will require imaginative thinking, bold approaches, and interdisciplinary collaboration," stated Coit D. Blacker, Director of the Freeman Spogli Institute and Chair of the International Initiative's Executive Committee. "The Executive Committee was encouraged to receive more than 35 proposals of an impressive caliber, and after careful review, to award these first grants," Blacker said.

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The Effect of Diagnosis with HIV Infection on Health-Related Quality of Life

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We sought to understand how diagnosis with HIV affects health-related quality of life. We assessed health-related quality of life using utility-based measures in a Department of Veterans Affairs (VA) clinic and a University-based clinic. Respondents assessed health-related quality of life regarding their current health, and retrospectively assessed their health 1 month prior to and 2 months after diagnosis with HIV infection. Sixty-six patients completed the study. The overall mean utilities for health 1 month before and 2 months after diagnosis were 0.87 (standard error 0.037), and 0.80 (0.043) (p0.005 by rank sign test), but the effect of diagnosis differed between the two clinics, with a substantial decrease in the university clinic and a small non-significant decrease in the VA clinic. The overall mean utility for current health was 0.85 (0.034), assessed on average 7.5 years after diagnosis. When asked directly whether diagnosis of HIV decreased health-related quality of life, 47% agreed, but 35% stated that HIV diagnosis positively affected health-related quality of life. Diagnosis with HIV decreased health-related quality of life at 2 months on average, but this effect diminished over time, and differed among patient populations. Years after diagnosis, although half of the patients believed that diagnosis reduced health-related quality of life, one-third reported improved health-related quality of life.

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Quality of Life Research
Authors
Douglas K. Owens
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Russian Resilience as a Great Power

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Two political scientists comment on Thomas Ambrosio's The Geopolitics

of Demographic Decay: HIV/AIDS and Russia's Great-Power Status (Post-Soviet

Affairs, 22, 1, January-March 2006).

Ambrosio's three indicators of great-power capacity, Russia's society, military, and economy, are reviewed in terms of his argument about how the projected effects of HIV/AIDS weakens each factor.

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Post-Soviet Affairs
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Michael A. McFaul
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CHP/PCOR Quarterly Update, winter 2006 issue

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This issue of CHP/PCOR's quarterly newsletter, which covers news from the fall 2005 quarter, includes articles about:

  • a study concluding that the implantable cardioverter defibrillator -- one of the most expensive medical devices on the market -- is worth its high cost, in appropriate patients, because it prevents sudden cardiac deaths;
  • the evolution and broad application of the Quality Indicators, a set of practical tools developed by CHP/PCOR researchers that are used by hundreds of U.S. hospitals, medical groups, health insurers, state health agencies and business coalitions to screen for quality problems;
  • a study finding that the Internet can be a valuable tool to help patients with stigmatized illnesses (such as mental illness) find information about and seek treatment for their illness;
  • CHP/PCOR-hosted seminars on global health themes, given by Jack Chow of the World Health Organization -- who discussed combating malaria, TB and HIV/AIDS -- and Dean Jamison of the NIH's Fogarty International Center, who discussed evaluating countries' performance on health; and
  • a prestigious national award won by two CHP/PCOR trainees at the annual meeting of the Society for Medical Decision Making.
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Improved Allocation of HIV Prevention Resources: Using Information About Prevention Program Production Functions

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To allocate HIV prevention resources effectively, it is important to have information about the effectiveness of alternative prevention programs as a function of expenditure. We refer to this relationship as the ldquoproduction functionrdquo for a prevention program. Few studies of HIV prevention programs have reported this relationship. This paper demonstrates the value of such information. We present a simple model for allocating HIV prevention resources, and apply the model to an illustrative HIV prevention resource allocation problem. We show that, without sufficient information about prevention program production functions, suboptimal decisions may be made. We show that epidemiologic data, such as estimates of HIV prevalence or incidence, may not provide enough information to support optimal allocation of HIV prevention resources. Our results suggest that good allocations can be obtained based on fairly basic information about prevention program production functions: an estimate of fixed cost plus a single estimate of cost and resulting risk reduction. We find that knowledge of production functions is most important when fixed cost is high and/or when the budget is a significantly constraining factor. We suggest that, at the minimum, future data collection on prevention program effectiveness should include fixed and variable cost estimates for the intervention when implemented at a ldquotypicalrdquo level, along with a detailed description of the intervention and detailed description of costs by category.

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Health Care Management Science
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Death and Development

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Analyzing a variety of cross-national and sub-national data, we argue that high adult mortality reduces economic growth by shortening time horizons. Higher adult mortality is associated with increased levels of risky behavior, higher fertility, and lower investment in physical and human capital. Furthermore, the feedback effect from economic prosperity to better health care implies that mortality could be the source of a poverty trap. In our regressions, adult mortality explains almost all of Africa's growth tragedy. Our analysis also underscores grim forecasts of the long-run economic costs of the ongoing AIDS epidemic.

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Publication Type
Working Papers
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Journal Publisher
CDDRL Working Papers
Authors
Romain Wacziarg

HIV/AIDS in China

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There are currently an estimated 840,000 people in China who are infected with HIV. The largest two groups that have been affected are injection drug users and former plasma donors. Recent demographic and economic changes in China could and may be fueling an increase in sexual transmission in China. Dr. Nancy Shulman will give a brief overview of HIV in China and the governmental response. Future collaborative efforts with Stanford will also be discussed.

Co-sponsored with the Center for East Asian Studies

Philippines Conference Room

Nancy Shulman Instructor of Medicine, Division of Infectious Diseases, School of Medicine, Stanford University Speaker
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