The reason cause-effect claims are so hotly debated is that they have implications for policy. If the death penalty does not work, why have one? If passive inhalation of smoke causes cancer, should public smoking be allowed? Cause-effect claims raise vital economic and political questions. They influence our decisions on matters ranging from law making to stanozolol suspension personal health.
The only way to test a cause-effect claim is to manipulate the suspected cause and measure the suspected effects. Like observational research, it sounds simple. But, as with observational research, there are many pitfalls or ways to make mistakes.