3. Different types of study designs

3.1 Descriptive studies

These studies describe the frequency, the distribution, and the development of a phenomenon.

They provide quantitative data on the extent of a disease and its risk factors. They involve cross-sectional studies or prevalence studies, in which measurements are taken in a set amount of time.

They have the problem of lacking information on the timing of events. Being easy to carry out, they are used to develop hypotheses that can be tested by analytical studies.