3. MEANING OF RATIO DECIDENDI
Latin for ‘reason for the decision’ . The ratio decidendi is the portion of the judgement which contains the principle or reasons or the legal rule on which the decision is based. Goodhart also defined it as the material facts of the case and the decision thereon. It is also sometimes defined negatively as the general rule without which the case would have been decided otherwise.
It is the ratio decidendi of the case that constitutes the binding precedent for subsequent cases having the same facts.

5. HOW TO FIND THE RATIO DECIDENDI
Wambaugh’s Inversion test explained in Chief Egbo and ors v. Chief Laguna &Ors (1998) 3 NWLR (pt. 80) 109
Goodhart’s test
Professor Julius Stone’s criticism of Goodhart
Ratio Decidendi in court with more than one judge

6. GOODHART’S TEST
(1) The principle of a case is not found in the reasons given in the opinion.
(2) The principle is not found in the rule of law set forth in the opinion.
(3) The principle is not necessarily found by a consideration of all the ascertainable facts of the case and the judge's decision.
(4) The principle of the case is found by taking account (a) of the facts treated by the judge as material, and (b) his decision as based on them.
(5) In finding the principle it is also necessary to establish what facts were held to be immaterial by the judge, for the principle may depend as much on exclusion as it does on inclusion.

7. CRITICISM OF GOODHART’S TEST
Professor Julius Stone asserted that Goodhart ought not to have attempted to lay down a prescriptive theory rather than a descriptive theory. It is also a mistake to expect a case to contain only one ratio. Rather it would have been more accurate to describe a technique which recognizes that the ration involves a process of abstraction and generalization.
The ratio might easily be particularized but may from the particular facts be generalized to cover many instances and situations as he illustrated with Donoghue v Stevenson. Thus the idea of the ratio is a flexible idea that is left to the court handling a case to decide what level of generality to apply

9. WAMBAUGH’S INVERSION TEST
Eugene Wambaugh’s test is based on the idea that the ratio decidendi is a general rule without which a different decision would have been reached in the case.
It was explained in Chief Egbo and Others v. Chief Laguna and Others (1988) 3 N.W.L.R (pt.80) 109 by Kolawole JCA as follows;
“In order therefore to determine the ratio decidendi of a case, it has been suggested that we should take the proposition of law put forward by the judge, reverse or negate it, and then see if its reversal would have altered the actual decision. If so, then the proposition is the ratio or part of it. In other words the ratio is a general rule without which the case would have been decided otherwise”

10. CRITICISM OF WAMBAUGH’S TEST
Sir Rupert Cross observes that the value of the test in determining the ratio of a case is undermined by the fact that is restricted to only cases with just one ratio. However it is valuable for determining what is not the ratio but merely an obiter

12. HOW TO FIND THE RATIO DECIDENDI
The ratio decidendi of a case is not determined from isolated dictum in the judgment. It is determined on considerations of the issues in the dispute between the parties and the facts pleaded and found in support of the contention of the issues. Hence every judgment ought to be read as applicable to the particular facts proved or assumed to be proved. The generality of the expressions found therein are not intended to be expositions of the whole law, but govern and are qualified by the particular facts of the case in which such expressions are to be found - See U.T.C. Ltd. v. Pamotei (1989) 2 N.W.L.R. (Part 103) 244, 293. – Karibi-Whyte JSC in United Bank for Africa Ltd v. Stahlbau GMBH & Co. Kg (1989) LPELR-SC.224/1988

13. RATIO IN CASES DETERMINED BY COURT OF MORE THAN ONE JUDGE
According to Obilade the rules that apply In this circumstance are
1. Where the Court is divided and the majority judgments are consistent with one another even though each majority judge relies on a legal principle different from that relied by any other majority judge, all the legal principles relied upon in the majority judgments constitute the rationes decidendi of the case
2. Where the majority judgments are consistent with one another and they are based on the same legal principle, that principle is the ratio decidendi of the case

14. RATIO IN CASES DETERMINED BY COURT OF MORE THAN ONE JUDGE
3. Where the majority concur in the result but the majority judgment are inconsistent with one another it is suggested that a proposition of law which is not supported by any majority and which is actually rejected by the majority should not be considered as the ratio decidendi. It woulD seem that such a case should not be cited as a binding authority for any proposition

15. CONCLUSION
The entire operation of stare decisis or binding precedents depends on the formulation of the ratio decidendi. As a student or a lawyer or even a judicial officer you cannot do well without properly understanding how the court arrives at its ratio decidendi. It is a practical skill which you would acquire by dint of diligent practice.
The only part of the judgment which is binding and which you can appeal against is the ratio decidendi. Make sure you familiarize yourself with the principles enunciated for determining the ratio decidendi, then apply yourself to thoughtful perusal of the judgments of the superior courts of record.