Experiments allow the study of research questions under controlled settings, such that the effects of the examined variables can be isolated.
The aim is to explore a possible relationship between one or more input/treatment variables and a response variable of interest, and to estimate the sizes of any treatment effects. With careful planning of the experiment, valid conclusions can be drawn, and the amount of information can be maximized given the available resources.
The research area was systematized by Ronald Fisher starting in the 1920s in connection with agricultural experiments. Fisher used statistical methods to plan experiments and formalized principles such as randomization, replication, and blocking. Many applications have since then been found in biology, medicine, and industry, especially within quality improvement and process optimization. Today applications are common in many research disciplines, including social sciences and economics.