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What is Epidemiology?

Epidemiology is an important contributor to public health, offering data gathering and analysis, research and results — all designed to improve community health and provide solutions and preventative measures.
A public health professional holding a marker, describing what epidemiology is

Understanding the Numbers
When reviewing job growth and salary information, it’s important to remember that actual numbers can vary due to many different factors — like years of experience in the role, industry of employment, geographic location, worker skill and economic conditions. Cited projections do not guarantee actual salary or job growth.

Epidemiology looks to find the answers to what, who, where, when and why/how a disease or other health-related event is occurring. It involves surveillance, investigation and the design, conduct, analysis and interpretation of research studies.

Dr. Elisea Avalos-Reyes, an adjunct faculty at SNHU“Epidemiology is the study of diseases. Epidemiologists study trends, rates, predictors and risk factors for diseases and other health-related incidents in specific populations,” said Dr. Elisea Avalos-Reyes, an epidemiologist and adjunct faculty at Southern New Hampshire University (SNHU). “A well-designed research study should consist of a team of epidemiologists and biostatisticians to ensure the study is methodologically and statistically sound.”

The Centers for Disease Control and Prevention (CDC) defines epidemiology as the study of the distribution and causes of diseases and other health events among populations. Epidemiologists use scientific and systematic data to look at the frequency and pattern of these events, as well as causes and risk factors. The populations they study can range from a neighborhood, school or city, to a state, country or the globe.

These studies provide a basis for action plans in a specific community. The data from these studies must be stringently evaluated. Data analysis is a key component for epidemiologists — whether it’s data they have compiled themselves or turning their eye to the work of others in the field.

What Does an Epidemiologist Do?

A graphic with a blue background and a white microscope icon Epidemiologists collect and analyze data to investigate health issues and demographic vulnerability to those issues while factoring in survivor trends that could be used to develop better treatments or prevention, according to the U.S. Bureau of Labor Statistics (BLS). 

Epidemiologists may work for state and local governments, addressing public health problems directly, or in research roles at universities or in affiliation with federal agencies, such as the CDC or the National Institutes of Health (NIH), BLS reported.

The roles and responsibilities of an epidemiologist can vary a great deal based on education, training, job experience and the needs of the organization or community served. 

Dr. Jamie Ritchey, an adjunct faculty member at SNHU“At Inter Tribal Council of Arizona, Inc., a good deal of my time is spent writing grants and planning and managing programs that support (the work of the) tribal health departments," said Dr. Jamie Ritchey, epidemiologist and adjunct faculty at SNHU. "While at Broward County Health Department, my primary responsibility was infectious disease outbreak response within the county.”

Day-to-day job duties can include data analysis and programming, grant and report writing, community health training and technical assistance, contact tracing and case interviews, Ritchey said.

Some of the duties of an epidemiologist, according to BLS, are:

  • Collection and analysis of data to find causes of diseases or health concerns using observation, interviews, surveys and samples
  • Communication of findings to health practitioners, policymakers and the public
  • Management of public health programs — planning, monitoring progress, analyzing data and seeking ways of improvement
  • Planning and directing studies of public health problems to find ways of prevention and treatment
  • Supervision of professional, technical and clerical personnel

“These analyses and reports are frequently used by government officials at various levels and other community leadership to make decisions about disease response and policy,” Ritchey said. 

Some issues that epidemiologists can work with, according to Ritchey, include:

  • Chronic diseases, like cancers, diabetes, depression and heart disease
  • Environmental exposures, including chlorine spills and lead abatement
  • Infectious disease outbreaks like COVID-19
  • Substance abuse and behavioral health, such as addiction and mental health

What Does an Epidemiologist Study?

Epidemiologists study disease, its causes and treatments in specific populations. There are many areas of research one can work in, said Dr. Dodie Arnold, public health adjunct faculty member at SNHU. 

Some areas of research in epidemiology include:

  • Cancer
  • Clinical
  • Clinical trial
  • Chronic disease
  • Infectious disease
  • Injury and accident
  • Perinatal
  • Pharmaceutical
  • Radiation

The results of study and research, and how the subsequent measures impact communities, are important parts of epidemiology work. 

For example, Avalos-Reyes said, epidemiologists also study salmonella and E. coli outbreaks and assess the impact of interventions — such as the reduction in disease and death as a result of banning vaping. “When you hear a news study discussing the mental health benefits of exercise or the importance of dieting, chances are, an epidemiologist helped design the study," she said. 

Find Your Program

How Do You Become an Epidemiologist?

A medical clipboard graphic with a yellow cross and a blue background There are many paths to becoming an epidemiologist, but most begin with a Master of Public Health (MPH) degree

“(An MPH degree) is a requirement to work for many health departments, nonprofits, universities or other government jobs as an epidemiologist, but not always. Public health nurses frequently work as epidemiologists as well,” Ritchey said. According to her, holding an MPH degree is often required for those who lead research at universities. 

When considering MPH programs, try to look for one accredited by the Council on Education for Public Health (CEPH), such as SNHU's. CEPH is an independent agency recognized by the U.S. Department of Education (ED), and their accreditation means that the program has met the standards. 

In an accredited MPH program, you can gain the skills you need to lead illness and disease prevention efforts, build community wellness programs and advocate for public health policy. 

Some foundational MPH courses can include:

  • Biostatistics
  • Epidemiology
  • Public health

In addition to these foundations, you may also take courses in a selected specialty topic area. At SNHU, for example, you can concentrate your MPH on global health.

Avalos-Reyes also recommended considering the topics of community health, environmental health, behavioral health and health administration as part of your education. 

Ritchey suggested completing at least one internship in an epidemiology department prior to entering a degree program.

Where Do Epidemiologists Work?

Epidemiologists can work in the public, private or nonprofit sectors, or in other capacities, such as academia or as an independent contractor, according to BLS. Epidemiologists in the private sector often conduct research for health insurance or pharmaceutical companies. In the nonprofit sector, job duties can include public health advocacy work, whereas research epidemiologists are rarely advocates because scientific research is expected to be unbiased, BLS reported.

Dr. Dodie Arnold, a public health adjunct faculty member at SNHUIn addition to state and federal public health agencies, career positions for epidemiologists can include ones at academic institutions as part of the teaching faculty and/or as part of a research team. But there are other options besides academia and the aforementioned sectors, Arnold said, such as consulting as part of an agency or as an independent contractor is one avenue. 

“Self-employment is also an option but usually comes after several years of experience," she said. "It's a great path and definitely worth pursuing. Self-employment is very different than being an employee.”

According to Avalos-Reyes, epidemiologists can work everywhere. “Most epidemiologists work for health departments, universities, government organizations ... or other large organizations (like) hospitals and pharmaceutical companies," she said. "Your preference in epidemiology will determine where you will work.”

Your preference might be collecting the data through research, or it might be evaluating that collected data (yours or others). 

“Although many roles are heavy on data analyses and interpretations, there are roles that focus mostly or exclusively on research design (also called research methodology) or implementation,” Arnold said. “Depending on your other skills and interests, it may also be easy to transition into other fields or positions that are more managerial in nature.”

Is Epidemiology a Good Career? 

Epidemiology can be a good career for those who want to investigate patterns and causes of disease and injury, according to BLS. The field is projected to grow 27% from 2022 to 2032, BLS reported, and in 2022, the median pay for epidemiologists was $78,520.*

Epidemiology can be a dynamic and fluid career, offering opportunities to contribute to public health in a variety of ways, including scientific research with the potential for real-world application. If you're drawn to solving complex health problems and contributing to greater causes, a career in epidemiology could be very rewarding. 

A degree can change your life. Find the SNHU health program that can best help you meet your goals. 

*Cited job growth projections may not reflect local and/or short-term economic or job conditions and do not guarantee actual job growth. Actual salaries and/or earning potential may be the result of a combination of factors including, but not limited to: years of experience, industry of employment, geographic location, and worker skill.


Kathleen Palmer is an award-winning journalist and writer.

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