A lab/controlled experiment is an investigation in which a hypothesis is scientifically tested, within a controlled environment, usually a laboratory. The key features are control over variables, careful measurement, and establishing cause and effect relationships.
Lab experiments are favoured by positivists, as they model their approach to research on the natural sciences. They allow for the collection of data in a reliable and objective way, which positivists prefer as they argue society should be studied scientifically so as to establish ‘social facts’
