Public Health Research and Epidemiology

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Unit PHR1: Research Skills (part I)

Module Overview / Unit PHR1 / Session 1

An Introduction to Public Health Research and Epidemiology

The objectives of this session are to:

  • Appreciate the role of science (and research) in the development of public health as a discipline.
  • Understand the importance of epidemiology through the ages.
  • Summarise some of the approaches used today in medical and public health research.
  • Explain the need for research and scientific literacy among public health practitioners as well as health professionals and the public more widely.


Please watch the video lecture for this unit - An Introduction to Public Health Research and Epidemiology.


1 - 2 - 3 - 4 - 5

Please read the Introductory chapter of Basic Epidemiology (Bonita, et al. 2006).

To access this resource, you will need to log in to Athens. Go to StudyNet's Online Library page, and when the message 'You can access Athens resources' appears on the right, you will then be able to access the ebook.

Biomedical research can be categorized in many different ways. In the context of epidemiology and public health, it is helpful to distinguish between:

  • Observational Research
  • Experimental Research

In observational research, the outcome of interest – perhaps the frequency of a disease in a population – is observed, noted and reported. There are surveillance-based approaches to acquiring these data. Cancer registries are one such example. Alternatively it may be feasible to collect data – sometimes once (a cross-sectional survey) or at repeated points in time (a cohort study). Observational approaches can be very useful for quantifying illness, and from this research it may be possible to identify health priorities and plan services accordingly. By comparing the frequency of disease in one population with that in another, it may be possible to infer why the differences in frequency exist. This may be the first step in determining the cause of disease (causation).

Experimental research goes further: in this type of research the aim is to establish the effect of an intervention in a given population over a pre-specified time period. A classic example is the randomised controlled trial of a pharmaceutical agent (drug). Experimental research can be very powerful but can also be more ethically questionable. Actively and intentionally exposing a patient to harm (without a commensurate capacity to benefit) is usually unethical.

These two approaches usually rely on numbers and answer questions such as "how common is the disease" or "does this drug work?" Because of their reliance on numbers, they are termed 'quantitative' research methods. Classically these approaches can be described as top-down, as they seek to confirm a hypothesis.

Yet there are often scenarios where we ask quite different questions. If we wanted to know what the public thought should be public health priorities, how would we ask this? Would we give them five boxes and ask them to rate tobacco control against cancer and air pollution? In fact, it might be more useful to find out why the public prioritised tobacco control over vehicular emissions. In this situation quantitative methods are limited.

When seeking to explore a subject we turn to qualitative research. Qualitative research applies very different approaches to answering research questions. Focus groups and semi-structured interviews are among the approaches that can add depth to the understanding of often-complex issues. In fact, qualitative research has the capacity to identify priorities and direct future research efforts. Despite this, qualitative approaches are frequently ignored or disregarded by quantitatively-trained scientists.

An increasingly common approach to research involves 'mixed-methods' research. Here, a combination of quantitative and qualitative methodologies can be applied such that the subject area can be examined in great depth and breadth.

The role of academics and epidemiologists is to devise and deliver approaches to answering important questions about the distribution and determinants of health. While not all public health practitioners may be academic epidemiologists, practitioners must be conversant in the language and science of epidemiology.

An understanding of epidemiology is both necessary but insufficient for a public health practitioner. Practitioners must be able to advocate on behalf of the public's health. To do this, they must be able to communicate epidemiological concepts to other experts and decision-makers, many of whom may not be well-versed in science, let alone biomedicine.

Epidemiological research is an eternal fountain of headline material for sub-editors the world over. Most journalists do not seek to mis-represent science, but they frequently do. The reason for this is fulfill the public's thirst for news. An important area and opportunity for public health is in using the press to communicate evidence-based health promotion. In order to do this, practitioners need the skills to communicate effectively. Nowhere is this more difficult than when communicating uncertainty. Like the public, the media want a definitive yes or no. In science this is often not possible.


So that’s the first session. Thanks for listening and reading.

Further resources

Podcasts: In Our Time, BBC Radio 4

Podcasts: More or Less, BBC Radio 4

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