Mariel Finucane wanted a career that would, in her own words, "have a positive impact in the world." It's in her nature -- or nurture: Her grandmother was a social worker, her grandfather a public schoolteacher. Her parents are both public-minded medical doctors: her father a geriatrician and her mother an infectious disease specialist. When she was just 13, Finucane spent her winter holiday "trying to bring positive energy" to the children in the pediatric oncology ward of a public hospital in Mexico, where her parents were volunteering during a 6-month sabbatical.
But, as Finucane's academic interests began to take shape, she found herself drawn to pure mathematics, which she saw "as pretty remote from the questions of economic equality and social justice and so forth," she says. "I thought I would have to choose between trying to make an impact and being able to do mathematics."
For a while, she pursued her two interests independently. In 2001, she enrolled at Smith College in Northampton, Massachusetts, to study math, eventually earning a bachelor's degree. The summer following her sophomore year she volunteered for WorldTeach , a nonprofit organization based at the Center for International Development  at Harvard University. After 1 week of intensive teacher training and learning Spanish, she taught English to secondary school students in a remote town in Costa Rica . She paid a substantial fee (in support of her airfare, overseas medical coverage, and stay with a host family) to participate in the program, but the cost was covered by a grant from her college.
In her third year at Smith, Finucane discovered a way to combine her interest in pure mathematics with her desire to make the world a better place. "I thought statistics was kind of dirty math ... and that it wouldn't be very interesting for me," she says. But that year, as she took her first class in statistics, "I realized that you could apply these pure ideas in a way that could potentially improve public health and benefit the world," she says. "That those two different interests of mine could come together and be used jointly was really very exciting."
That same year, she received a training grant to spend part of her summer at the Desmond Tutu HIV Centre at the University of Cape Town  in South Africa. There, she helped implement a study of HIV prevalence, providing HIV/AIDS education in schools and churches, training field workers, and dealing with the study's logistics. "I got to go to the clinics and actually see on the ground how the data was collected," she says. In her final year of college, she wrote an honors thesis with statistician Nicholas Horton on the statistical analysis of HIV antiretroviral therapy adherence among patients in Boston.
After graduating in May 2005, Finucane returned to WorldTeach, this time spending a year in the Marshall Islands  with the person who would become her husband -- Brett Simchowitz, a medical student at the University of California, San Francisco, whom she met in Costa Rica; he, too, was a WorldTeach volunteer there. In the Marshall Islands, they both taught English and together developed a "culturally appropriate" sexual health and family planning curriculum for primary school children. This time there was no fee; Finucane even received a small stipend.
Upon returning to the United States, Finucane pursued a Ph.D. with Chris Paciorek in the Department of Biostatistics at the Harvard School of Public Health  in Boston. There, she studied the contribution to global death tolls, and their trajectories over time, of cardiometabolic risk factors (including high blood pressure and obesity) and undernutrition.
She started her graduate training with the goal of joining an international nonprofit organization to fight infectious diseases in sub-Saharan Africa, and at first she found her research too descriptive. "I felt like maybe I was a little removed from what I'd most like to be working on," she says. "But then I came to realize that having a deep, rigorous, quantifiable understanding, for example, of how big child undernutrition is as a problem [is] really important" as a foundation for seeking solutions, she says.
Finucane is currently doing a postdoc in the same group, continuing her childhood undernutrition research. She has decided to pursue an academic career, hoping to spend time in developing countries as part of an academic appointment. She intends to seek research projects "where the statistical challenges are complex and the data sets really merit methodological innovation ... [but where] the problem that the data set is describing or the solution that the data set is proposing to have can have a real impact."
What impact has volunteering had on Finucane's career? "It motivates me." It also helps her put her work in context. "There's a possibility for public health research ... and for these big statistical models and large data-analysis projects to get undertaken kind of in a vacuum," she says. "Having lived in these small communities and having seen the kinds of health problems and health infrastructure that exist there ... help[s] me to be a better statistician and to have a deeper understanding of what lies behind the numbers."