What is a prospective study

A prospective study (lat. prospecto: ausschauen) is the examination of the hypothesis of the medical or psychological effectiveness of a treatment method with prior determination of which hypothesis should be examined. In particular, the data according to the hypothesis are collected in contrast to the retrospective evaluation of already existing data.

The term prospectively is used in high-level language in the sense of "foresight", "the possibility of" and "regarding further development".[1]

The prospectiveness of a study says something about the timing of the creation of hypotheses and data collection. The data in such a study are collected specifically for testing the hypothesis after the hypothesis has been drawn up. One advantage is that the data material can then be tailored precisely to the requirements of the study.

In a retrospective study, however, one can e.g. For example, after setting up the hypothesis, search for existing databases and take data from them - these may not exactly match the requirements of the study, on the other hand this procedure is often less costly and time-consuming.

Prospective studies can be divided into experimental prospective studies and observational prospective studies. In the experimental study, the examiner usually randomizes the strength of the independent variable and its assignment to the individual test subjects. Such an allocation does not take place in the observational study.


If one wants to study the effect of smoking on the development of lung cancer, there are two prospective approaches:

  1. Prospectively observing: the test persons are asked how much they smoke, then classify them into groups and examine whether they develop lung cancer at different rates.
  2. prospective experimental: You take a group of test persons, divide them into subgroups by randomization and tell each group how many cigarettes they should smoke per day and then examine the connection.

As you can see, the second solution is not always ethically justifiable, although theoretically it achieves the safer results because it is e.g. B. prevents that there is a third quantity that affects both the independent variable and the dependent variable.

See also

Individual evidence

  1. ↑ Duden, vol. 5. The foreign dictionary. 1997. p. 665