Experimental manipulation describes the process by which researchers purposefully change, alter, or influence the independent variables (IVs), which are also called treatment variables or factors, in an experimental research design. This process allows researchers to explore causal relationships between IVs and dependent variables (DVs), which are also referred to as outcome or criterion variables, of interest in a particular study. Specifically, manipulation of an IV allows researchers to explore whether the IV causes change in a study’s DVs.

To further explain the process of experimental manipulation, this entry first outlines types of IVs that might be manipulated in an experimental design and specific approaches to manipulating IVs. Next, manipulation checks, an important step in ensuring that the manipulation of the IV has been ...