Internal validity is the ability for a study to show the relationship a treatment and the outcome (Myers & Hansen, 2012). External validity is how well a study outcome can be generalized (Myers & Hansen, 2012). Researchers have various resources available to help increase the internal and external validity of experiments. External validity of an experiment can be proven by conducting further studies. Aggregation, multivariable designs, nonreactive measurements, field experiments, and naturalistic observations are five techniques that researchers can use to help increase external validity of experiments (Myers & Hansen, 2012). In order to help increase internal validity of experiments researchers can ensure that no outside influence could be responsible for the results otherwise known as confounding. Another method that can be used to help increase internal validity is by using blinding. Blinding can be achieved by making sure that the participants are not aware of which variable they are being exposed to.