Independent variables are those which researchers believe causes an outcome on another variable, the dependent variable. In experimental research, the independent variable is manipulated by the researcher and applied to the subject or subject group to measure the effect of the independent variable on the dependent variable. In nonexperimental research, the independent variable is the variable which, although not manipulatable, is the variable from which causal inference is implied.
Citation: Lewis-Beck, M., Bryman, A., & Liao, T. (2004). The SAGE encyclopedia of social science research methods (Vols. 1–3). Thousand Oaks, CA: SAGE Publications. https://doi.org/10.4135/9781412950589