Once the magnitude and distribution of a health problem and its possible determinants have been established, anempts to prevent, treat, or control the problem by intervening on one or more of the determinants should be made.

In a descriptive study, therefore, the magnitude and distribution of a health problem in a specified population is studied in terms of TIME (when did it occur?), PLACE (where did it occur?) and PERSON (which groups are ...

Randomised controlled trials (RCTs), although regarded as the best method for assessing the efficacy of an intervention, have several shoncomings and may be impossible to conduct, for example in the case of harmful risk ...

In the first article in a series on epidemiological research methods, we describe the origins and uses of epidemiology and introduce the different types of epidemiological study design.

The goal of epidemiology is to improve the health status of human populations. In our series thus far we have srressed the need to use the correct design for epidemiological studies, a sampling scheme that yields ...

Follow-up studies (also called prospective or cohort studies) are used to determine the natural history of disease, to evaluate the role of risk factors in causation or association, to determine the prognosis of patients ...

The need for writing a good protocol is still paramount and applies not only to randomised controlled trials (RCTs), but to all research projects. Writing a good protocol reflects good planning, and in this paper ...