Making Medical Sense of Numbers: Rebecca Hubbard, Pitt's First African American Marshall Scholar, Builds Successful Career as a Biostatistician

Rebecca Hubbard

Pitt alumnus Rebecca Hubbard transforms the range of human experience into numbers that matter. A biostatistician, she works within the vague confluence of mathematics and the health sciences.

When doctors want answers and guidance from medical studies of vast populations—When is early Alzheimer’s most likely to be detectable? What is the risk of being erroneously recalled for additional imaging or biopsy following a mammogram?—Hubbard is there to make sense of the numbers. Stories become samples. Coincidences become probabilities. Conversations become data. And that information assumes a meaning far beyond a single patient.

“A good statistician interprets how the numbers actually relate to human health,” said Hubbard, an assistant investigator in Seattle’s Group Health Research Institute and a professor of biostatistics at the University of Washington. “Statistics is more than math; it’s 50 percent communication. Statisticians bridge a gap between epidemiologists and doctors in an effort to explain how the experiences of multiple individuals apply to medicine as a whole. That’s a fun part of this job.”

Hubbard was the first person in her family to attend college. Having an affinity for math, she entered Pitt in 1996 with an interest in epidemiology. Her academic path lead, with seeming logic, to her current career: After graduating in 1999, she was awarded a Marshall Scholarship in 2000 to study at the University of Edinburgh, where she received a master’s degree in epidemiology in 2001, and Oxford University, where she earned another master’s degree (with distinction), this time in applied statistics in 2002. She completed her PhD degree in biostatistics at the University of Washington in 2007.

Yet, beginning at Pitt, Hubbard’s professional maturation was subject to a surprising—and significant—influence from trees, although she was a reluctant nature lover at first. As a young bookworm in suburban West Chester, Pa., Hubbard was never invigorated by the compulsory family trips to the forest, unlike her country-born mother.

“She’d drag us out to collect wildflowers, and I didn’t appreciate it at all,” Hubbard recalled. “She wanted us to enjoy the outdoors, but I just wanted to sit in my room and read. It wasn’t until I got to Pitt that I found myself finally developing that fondness for the wilderness my mother tried to instill.”

Her mother’s zeal went beyond cultivating her children’s appreciation of nature, Hubbard said. Although Hubbard’s parents did not attend college, their children’s attendance was rarely in doubt.

“My parents were from farming communities in Delaware,” Hubbard said. “I went to a competitive high school where most of the kids’ parents went to college. My parents had jobs rather than careers, and I’m not sure they even knew what college was all about. But my mother was adamant that I go.”

Hubbard initially pursued microbiology at Pitt, but her interest strayed to a far larger subject—epidemiology. She enrolled in the ecology program in the Department of Biological Sciences in Pitt’s School of Arts and Sciences with ecology professor Walter Carson as her advisor: “Ecology’s the same thing as epidemiology, just not in humans,” she said.

Hubbard conducted research at Pitt’s Pymatuning Laboratory of Ecology—about two hours north of Pittsburgh—on new growth in tree-fall canopy gaps. Dead branches from the forest’s tallest trees crash through the tree cover to produce shafts of sunlight for which other plant species immediately compete. She predicted the likelihood of a certain species occupying the gap based on such characteristics as its susceptibility to predators or, as in the case of blackberries, sheer aggressiveness.

“So much of what I do now is based on that type of model,” Hubbard said. “I calculate the probability of a disease’s outcome based on characteristics.”

After receiving her bachelor’s degree in ecology and evolution from Pitt, Hubbard progressed to human health. Among the projects she is now pursuing is a study on Alzheimer’s disease that she joined as a postdoctoral researcher at the University of Washington’s National Alzheimer’s Coordinating Center. The lead researchers want to investigate cognitive changes prior to the onset of clinical disease when cognition fluctuates between normal and impaired. They seek to better understand how early impairment is associated with the pace at which Alzheimer’s fully develops. Hubbard is helping quantify the factors—environmental, emotional, etc.—associated with that progression.

She’s also working with the National Cancer Institute’s Breast Cancer Surveillance Consortium to tabulate the risks and benefits of routine mammograms, particularly the odds of receiving a false-positive exam result after multiple screening mammograms.

Another current project reinforces Hubbard’s fascination with biostatistics—especially in humans. Unlike trees, people maintain personal perceptions of their health. Hubbard is working on a study at the University of Washington gauging how people’s perceptions of their health align with the actual states of their health. Older adults were asked to self-report on their health over an eight-year period. Interestingly, many of the people surveyed reported their health as good as long as it didn’t change, even if objectively they were quite impaired, Hubbard said. Those responses suggest that people are quite resilient and can experience a good quality of life in spite of physical limitations once they have stabilized.

“People become accustomed to the state they’re in and someone who is stable may actually be doing just fine,” Hubbard said. “Respondents who rated their health as good recognized that their health is stable and valued the functional ability that they still had. The important point is that how people feel about their health is, in a real sense, the true measure of their well-being—if someone is stable and subjectively feels that their health is good, who are we to say otherwise? Just asking people a simple question is often the best way to get answers.”