Controversy is a state of prolonged dispute or debate, usually concerning a matter of conflicting opinion or point of view.
Opinion articles present the author’s viewpoint on the interpretation, analysis, or methods used in a particular study. It allows the author to comment on the strength and weakness of a theory or hypothesis. Opinion articles are usually based on constructive criticism and should be backed by evidence 1).
Such articles promote discussion on current issues concerning science. These are also relatively short articles.