Aresearcher interested in establishing that there is a causal relationship between variables is most interested in validity. artificial linear internal construct

He is more interested in the Internal Validity. Internal validity is of significate importance in scientific studies, and indicate if the variable analyzed is the cause of the effect obtained in the research, or whether the effect obtained is the product of another variable. For example, in an investigation analyzing the effect of anxiety on test results, care should be taken not to study other effects that may affect test results, such as fatigue or lack of study.