Causal research, is the investigation of (research into) cause-relationships.[1][2][3] To determine causality, variation in the variable presumed to influence the difference in another variable(s) must be detected, and then the variations from the other variable(s) must be calculated (s). Other confounding influences must be controlled for so they don't distort the results, either by holding them constant in the experimental creation of evidence. This type of research is very complex and the researcher can never be completely certain that there are no other factors influencing the causal relationship, especially when dealing with people's attitudes and motivations. There are often much deeper psychological considerations that even the respondent may not be aware of.
There are two research methods for exploring the cause-and-effect relationship between variables: