The true experiment
An experiment is an attempt to empirically verify or corroborate the hypothesis of a causal relationship between variables. Experiments cannot demonstrate causation, only covariance; they are designed to measure the degree to which a relationship exists between the identified variables (Field and Hole, 2002). Covariance assumes temporal precedence of the independent and the elimination of all other variables from the research context. For this reason only the laboratory setting can offer a suitable environment for the true experiment. Here test variables can be controlled and unwanted variables removed; this allows inference that Y (effect or DV) is a direct result of X (cause or IV).