Controlling experimental variables

• Operationalising variables is the process of defining the variables in a way that allows them to be measured. eg. number of people in a group. This is done so that the research is replicable, establishing reliability.
• The independent variable is the variable that is manipulated by the researcher to determine the effect on the dependent variable.
• The dependent variable is the outcome of the experiment and is the variable that is measured. by the researcher.
• extraneous variables are variables that are not directly related to the independent variable but may affect the dependent variable.
• Examples of extraneous variables are age or gender.
• Internal validity: the degree of which the results of the study are due to the independent variable and not due to other factors.
• external validity: the extent to which the results of a study can be generalised to other populations.
• ecological validity is the extent to which the findings of the study can be generalised to the real world.
• population validity is the extent to which the results of the study can be generalised to the population as a whole.
• historical validity is the extent to which the research findings are still generalizable to other situations over a period of time.
• mundane realism refers to how a study reflects real-world situations and how the research environment is similar to experiences that occur in reality.