Experiments and Experimental Design

Experiments are a type of quantitative research method used to examine questions of causal relationships. Specifically, experimental designs allow researchers to determine whether one or more independent variables (IVs; also called treatment variables or factors) significantly predict one or more dependent variables (DVs; also referred to as outcome or criterion variables) when all other factors are held constant. In true experimental designs, IVs are manipulated by the researcher to determine their effect on DVs. To do so, researchers place participants who have been sampled from a single population with common characteristics into experimental conditions or control groups using random assignment. Preexperimental designs involve the examination of the influence of manipulated IVs on DVs without the element of control required for true experiments. Quasi-experimental ...