Overview of research designs.

The aims of this paper are twofold. Firstly, to describe the obstacles that lie in the way of the researcher establishing the truth and how these may be dealt with in terms of research design. Secondly, to provide an overview of the different designs and the trade offs involved. The aim of research should be to establish the truth and research design aims to minimise or exclude the threats to the internal validity of the study (that is, that the conclusions are warranted by the observations). These threats are bias, confounding, and chance.