Understanding the Different Types of Epidemiology

When major health events strike communities, officials and healthcare providers turn to epidemiologists. Epidemiology is the science of how illnesses, injuries and health behaviors affect entire populations. Epidemiologists are the researchers and investigators behind public health, analyzing trends at a high level so policymakers and providers can take appropriate action.¹

Science has uncovered 212 new infectious pathogens since 1950, with 52 emerging since 2000 alone.² Epidemiologists have dedicated their careers to understanding these illnesses and other health trends, working in the background to keep people safe.

There are four main types of epidemiology, plus many areas of specialization. This article explains what each of those four involves, how they differ and how they intersect. You’ll learn the role of each type in keeping communities safe and discover how you can build a career in this in-demand field.

What Are the Four Methods of Epidemiology?

Epidemiologists typically divide the field into descriptive, analytical, experimental and applied epidemiology. If you're interested in a rewarding career influencing public health, you're likely to find a good fit among them.

Descriptive Epidemiology

Between January and July 2020, the public health community went from knowing nothing about a "pneumonia of unknown etiology" to identifying SARS-CoV-2 as a novel coronavirus that spreads through the air, with known risk factors and testing available to confirm etiology.³ Advancements like these are the direct result of descriptive epidemiology: a discipline that focuses on gathering information.

Descriptive epidemiologists research and report on the facts behind public health events. They primarily look at four of the five W's:

1. Who: What populations were affected? Epidemiologists look for patterns by finding common threads. They look at demographic factors, such as age, race and gender, as well as socioeconomic and cultural commonalities.
2. What: The goal is to identify the event or diagnosis as precisely as possible. Each detail provides additional direction for further study.
3. When: Outbreak timelines help public health experts to understand risk factors and the possible effectiveness of control measures.
4. Where: Tracking a health event requires knowing where the affected people live, work and receive treatment.

By identifying patterns and trends in these four components, descriptive epidemiologists generate research questions that power the next stage of understanding. Early in the recent pandemic, for example, descriptive data on COVID-19 cases led epidemiologists to propose airborne exposure, launching years of research and debate.⁴

Analytical Epidemiology

When descriptive epidemiologists have identified enough information about a health event, analytical epidemiologists take the next step. Relying on data analytics and direct-comparison studies, these experts test hypotheses to identify causes and risk factors.

Comparison studies look for differences between two groups that are otherwise similar, except that one has the disease under investigation. These studies help epidemiologists identify potential causes, which they evaluate via follow-up research.⁵

The best analytical epidemiologists approach their work with an unwavering focus on detail and a genuine concern for public health and well-being. It's a perfect pathway for mathematically inclined public health professionals and for those with a background or interest in data analysis.

Experimental Epidemiology

Of the several different types of epidemiology, this has the closest connection to laboratory science and medical testing. Experimental epidemiologists construct models to test hypotheses regarding disease prevention and treatment, with potentially lifesaving results.⁵

Experimental epidemiologists must have strong ethical convictions and a sense of judgment driven by compassion. This became evident in the winter of 2021, when the United Kingdom approved a "human challenge" trial to better understand SARS-CoV-2.⁶ Carefully developed eligibility criteria and oversight allowed epidemiologists to gather necessary intelligence on immune responses.

"We now have a much greater understanding of the full range of immune responses, which could provide a basis for developing potential treatments and vaccines that mimic these natural protective responses," said senior investigator Dr. Marko Nikolic.⁷

Applied Epidemiology

Once other types of epidemiologists have studied and analyzed the minute details of a disease, applied epidemiologists apply that work on a broader scale. Their tasks, according to the Council of State and Territorial Epidemiologists, are to:

• Develop and track interventions
• Evaluate public health and health care responses
• Communicate data to the public and health professionals
• Stress the importance of epidemiology⁸

Applied epidemiologists were behind many of the interventions that protected public health during the worst of the COVID-19 pandemic, from early social distancing measures to vaccination distribution policies.⁹ They investigated evidence-based lockdown alternatives, assessed political responses and observed disparities in outcomes.¹⁰

Epidemiologist Dr. Caitlin Rivers courageously spoke before U.S. lawmakers to advocate for a nationwide plan to strengthen testing, contact tracing and health care system support.¹¹ In doing so, she proved the power of caring, committed epidemiologists as advocates of public health.

Specialized Areas Within Epidemiology

As the body of epidemiologic knowledge has grown, the field has evolved to include specialized areas of study. Some epidemiologists work within a particular medical specialty, such as cancer, neurology, chronic illness or cardiovascular disease. Others focus their work on specific aspects of public health or disease transmission. Rewarding career opportunities exist in areas such as:

• Infectious disease
• Environmental health
• Hospital epidemiology
• Genetic and molecular epidemiology
• Injury trends
• Public health preparedness¹²

Specializing allows epidemiologists to work on targeted prevention and intervention approaches, such as developing strategies to boost healthcare staffing during the COVID-19 pandemic.¹³

Become the Epidemiologist the World Needs

Epidemiology is one of public health's most versatile and consequential disciplines and, as this overview suggests, the range of careers it supports is remarkably broad. Whether your interests lie in infectious disease, chronic illness, clinical research or public health policy, a graduate degree in epidemiology can equip you to pursue them at the highest level.

Kent State University offers two online graduate programs for public health professionals ready to take that step: the STEM-designated online Master of Science in Clinical Epidemiology and the STEM-designated online Master of Public Health in Epidemiology. Both programs are accredited by the Council on Education for Public Health (CEPH) and the Association of Schools and Programs of Public Health (ASPPH), delivered 100% online with the flexibility working professionals need, and taught by faculty who are active researchers and recognized leaders in their fields—scientists whose work is funded by institutions including the National Institutes of Health, the Robert Wood Johnson Foundation and the Centers for Disease Control and Prevention.

The online MS in Clinical Epidemiology is designed for professionals drawn to research: building sophisticated competency in biostatistics, study design and research methods that prepare graduates for careers as research scientists, clinical trial managers and data scientists. The online MPH in Epidemiology takes a broader public health lens, developing expertise in statistical analysis and disease investigation for graduates pursuing roles in disease surveillance, outbreak investigation and public health research across government, healthcare and nonprofit settings.

In small online classes, Kent State faculty bring frontline expertise directly to you, wherever you are. You'll also build a network of peers and practitioners that can open doors throughout your career. And with no GRE required and the ability to complete your degree in as few as 24 months, both programs are designed to move you forward efficiently and affordably.

Epidemiologists are in high demand: the U.S. Bureau of Labor Statistics projects 16% job growth for epidemiologists between 2024 and 2034, which is much faster than the national average.¹⁴ The question isn't whether the field needs you. It's where you want to make your mark.

To learn more about the online MS in Clinical Epidemiology or the online MPH in Epidemiology at Kent State, including admissions requirements and upcoming start dates, reach out to an admissions outreach advisor today. Each one is ready to answer your questions and help you take the next steps toward a more influential career in public health.