Ratio Decidendi. [Latin, The ground or reason of decision.] The legal principle upon which the decision in a specific case is founded. The ratio decidendi is also known as the rationale for a decision. See: authority, documentation.What's the difference between obiter dicta and ratio decidendi?
The main difference between ratio and obiter dicta is the information under scrutiny. For example, ratio decidendi refers to the facts of the case, those things that no one can debate. Obiter dicta, on the other hand, is everything in between. Obiter dicta translates to “by the way,” and refers to information that a person says, “in passing.”.When does ratio play a role in a case?
Where ratio plays into both of these situations is that it helps form the basis for the decisions in either case. Therefore, in cases where binding precedent exists, courts would do well to pay particular attention to the ratio in these cases.When is the ratio of a decision not binding?
The difficulty in the search for the ratio becomes acute when in the decisions of the Court of Appeal or the House of Lords, more than one judgment is promulgated. A dissenting judgment on the point is not binding and cannot be the ratio.