Decoding the Differences: A Guide to Careers in Epidemiology and Biostatistics

Often described as the foundation of public health, epidemiological studies focus on the “distribution and determinants” of disease within a population¹.  Epidemiologists are almost like the detectives of public health, tracking disease incidence, burden, and their cost effect on the population. People who work in epidemiology want to understand how the prevalence of a disease may ebb and flow over the years and the mechanism of spread driving the outbreak.

One of the most famous examples of epidemiology, and arguably one of the first instances of this modern practice, is the story of Dr. John Snow (no, not the guy from Game of Thrones) and the Broad Street water pump.

In 1866, British physician Dr. John Snow took note of a Cholera epidemic among patients in his London practice². At the time, sanitation in London was lacking and with an ever-expanding population, deadly cholera outbreaks occurred regularly³.  Moreover, germ theory was not yet widely accepted, leading most physicians, including Dr. Snow, to believe that “bad air” was the culprit of almost every infectious disease in existence⁴. Wanting to save lives, Dr. Snow decided to map all instances of Cholera in the area and when he did, he noticed a pattern: Most incidences of the disease occurred in people who got their water from the Broad Street water pump. Excited by his findings, Dr. Snow took his map to the city council who found it convincing enough to shut down the water pump⁵. Within weeks, the Cholera outbreak was over and Dr. Snow had inadvertently created the practice of epidemiology.

If you decide to pursue epidemiological studies, you will undoubtedly hear this story a few dozen times, but it’s an excellent example of the role of an epidemiologist. Using data analysis and observation, epidemiologists track the incidence and prevalence of disease and take action to resolve the issue.

Although infectious disease epidemiology is the most well-known application of the practice, modern epidemiology is also used to track everything from chronic disease to mental health conditions. Today, epidemiologists are also able to model the likelihood of a disease using risk factors and comorbidities to preemptively address public health concerns.

Like epidemiology, biostatistics similarly uses health data to assess possible points for health improvement within the population. Where the two fields differ, however, is the kind of data that each expert uses. Epidemiology is purely observational, using real-world incidences to uncover a cause and implement a fix. Biostatistics, on the other hand, can use experimental data or data gathered from healthcare settings.

Biostatisticians are interested in collecting, analyzing, and interpreting health information like medical records, vital statistics, or clinical trial data to assess the efficacy of a treatment intervention⁶. Using statistical methods, biostatisticians can then identify populations that are more susceptible to a disease or pinpoint weak points in a healthcare system that can affect patient outcomes.

Biostatistics also has broad applications today, ranging from spaces in hospital improvement strategy to clinical trial analysis for the application of a new drug to the FDA. Biostatisticians also frequently use survival analysis, a statistical method that assesses how long patients survive in clinical trials⁷. Odds are, a biostatistician was involved in the analysis that proved the Advil in your medicine cabinet was safe and effective enough for the general public to buy over the counter.

Unlike epidemiology, biostatistics utilizes sample data to assess how an intervention might affect the population, ideally to find biomedical science innovation that can work for everyone based on rigorous statistical analysis of sample data.

While there is a difference between the kind of data each uses, biostatistics programs and training paths for epidemiology are very similar. In fact, many programs currently offer courses of study that combine the two fields. The CUNY School of Public Health MPH in Epidemiology and Biostatistics and UC Berkeley’s MPH in Epidemiology and Biostatistics are just a few examples of programs with combined curriculums. While the MPH degree is a popular course of study, the MSc, doctorate, and PhD are also all viable options.

Regardless of which area you’re more interested in or which degree you choose, both fields require an understanding of statistics and data analysis. Building on these skills, epidemiology also requires an advanced understanding of causal inference, or the ability to statistically conclude that a cause undoubtedly leads to the observed effect. Biostatistics additionally requires a more robust understanding of statistical theory and methodology as well as study design. Given their involvement in clinical trial research, it’s also helpful for biostatisticians to be well-versed in health services research and medical terminology.

Recently, universities have also begun incorporating health informatics and data science education into both curriculums. Data science is the practice of manipulating and extracting information from large data sets, incorporating computer science techniques that now have applications in epidemiology and biostatistics⁸. For example, Columbia University offers a certificate in Applied Biostatistics and Public Health Data Science as part of its MPH program. As a graduate of this program, having exposure to data science techniques is incredibly helpful for manipulating data in the real world.

Regardless of which field you decide to pursue, career outlooks for both fields are positive for the next decade. Epidemiology and clinical epidemiology jobs are anticipated to grow by 19%⁹ while jobs in statistics fields are anticipated to grow by 11%¹⁰, higher than the average rate of growth for all jobs of 4%.

For biostatistics degree holders, jobs are available in health systems management, private industry, and research institutes. As discussed, biostatisticians can assist in clinical research at universities or hospitals. Within the pharmaceutical industry, biostatisticians are in demand to work within the drug development life cycle. Roles in government and nonprofit organizations are also available for those who want a more policy-oriented role. Because of the high degree of technical proficiency, biostatisticians are equipped to work in a wide variety of industries. 

Similarly, epidemiologists can also work in an array of settings. Research institutions and academia are always popular options, but clinical epidemiologists are also needed in hospital and healthcare settings. Infection control units in hospitals can provide a fascinating career that limits the spread of disease within a hospital. Throughout the COVID-19 pandemic, for instance, hospital epidemiologists had to figure out infection and disease control in real-time as the pandemic progressed¹¹.

In either field, graduates can expect a career involving data analysis, ultimately improving population health.

Now that we’ve discussed each subject, how do you decide between epidemiology and biostatistics? Fortunately, many programs are now interdisciplinary and will give you an understanding of each field, but deciding which to pursue as you search for a job can be more difficult. Below are a few tips to help guide you through the process:

In the end, both are great choices that offer fascinating career paths in the field of public health.  If you’re struggling to envision your career in the field, reach out to current professionals and ask for an informational interview. Maybe seek the advice of people working in positions you’re interested in at local public health departments or hospitals; ask to shadow for a day. Perhaps find a way to intern with an organization that stands out to you. More often than not, current professionals are ready and willing to offer advice to the next generation. Start making some LinkedIn connections and see where they lead you!

Both epidemiology and biostatistics offer fascinating career paths in public health. Utilizing health data and statistical methods, both fields aim to improve populations health, just from slightly different angles.  

While epidemiology is interested in investigating the causal link between an event and a disease outcome at the population level, biostatistics uses experimental data to determine which treatment options are statistically meaningful for a sample and then applies these findings to the population. Increasingly, universities across the country are acknowledging the interrelatedness of the two fields, creating programs that offer training in both. As data science continues to evolve as a profession, there's an added opportunity to expand applications to public health even further, creating even more exciting opportunities for upcoming graduates.   

Regardless of which subject you’re more drawn to, both offer the chance to make meaningful, data-informed changes in public health policy and research.

As you progress on your public health career journey, keep in mind that options in the field of epidemiology and biostatistics are endless. Reach out to professors, your university’s career office, people currently working in the field, and current students to ask for their advice and guidance. Do your research but don’t forget to enjoy the process! Epidemiology and biostatistics are dynamic fields that have a lot to offer in a career.