In this study, court decisions are classified in terms of procedural law and examined in the context of the effect of a court decision on other court decisions. The court decision, as a textual product given by the judge according to law, equity and conscientious conviction, is analysed in terms of containing principles. In a court decision, if the abstract norm is clear and the judge applied it to the concrete case by the deductive method, he/she did not engage in a unique mental action. Such decisions are case decisions or application decisions. In this respect, after it has been demonstrated that not all court decisions have the characteristics of jurisprudence, the court decisions that are taken into consideration in order to ensure similar decisions in precedent cases and therefore are not binding have been evaluated. In this respect, the persuasive power of precedent case law as a requirement of legal stability has been revealed. The value of precedent as a source of law, i.e., the value of a jurisprudence as a source of law, is explained by pointing out the differences between Continental European Law and Common Law. At this point, it has been determined that whether a court decision is bound by other court decisions or not stems from the relationship between the legislature and the judiciary, in other words, from the view of the law and the judge. On the other hand, in addition to the fact that a court decision contains a principle, the notion of a jurisprudence, i.e., the concept of constant jurisprudence, is discussed within the framework of jurisprudence constant (constant jurisprudence), which is a Continental European jurisdictional law theory. While the concept of constant jurisprudence is seen in the decisions of the Council of State as the precedent that courts and even administrations take care to comply with, it has been revealed that this may actually correspond to an institution from French law. In this respect, the doctrine of jurisprudence constant, which is accepted as the Continental European equivalent of the doctrine of stare decisis (precedent decision) in common law, has been analysed within the framework of both an institution and the concept of the case law seen in the decisions of the Council of State. It is analysed how a constant jurisprudence is formed and how this jurisprudence may impact the judge’s decision. There is a need for a certain time for the formation of a constant jurisprudence. Case law applied for a certain time will also prove its durability.  The fact that the court-issuing the decision is a higher-ranking court and that the decision is unanimous is important for it to be rendered unanimous. In the decisions of the Council of State, the broad interpretation of the interest of the inhabitants of the town in filing a lawsuit regarding zoning applications, environment, historical and cultural assets, the liability of the administration for acts of terrorism should first be based on fault liability and then, if there are conditions, on strict liability, and in the absence of these cases of liability, an investigation should be conducted according to Law No. 5233. It is argued that the criticism and contributions to be made by the doctrine in the decision review journals will be useful for the follow-up of the constant jurisprudence and criticism of the jurisprudence before it becomes constant. Within the scope of the study, the deviation of the court from the constant jurisprudence in administrative jurisdiction is also discussed in the context of the prohibition of surprise decisions. In one of the decisions of the Council of State, the prohibition of a surprise decision is addressed in the context of the right to be heard, but a surprise decision is a concept that can have a broader meaning. In this respect, making a decision different from the case law without a justifiable reason may violate the prohibition of a surprise decision. The compatibility of the principle of ex officio investigation and the prohibition of surprise decisions has been discussed within the framework of administrative jurisdiction law as a branch of procedural law. It is expected that the judge, who will decide differently from the established jurisprudence, will give the parties the opportunity to present their final statements before rendering his/her decision. The study also evaluates the connection of the unification of case law, which is an institution specific to Turkish procedural law, with the case law considering judicial decisions. As seen in the decisions of the Council of State, if a case law has become a case law, it should not be subject to a unification of the case law decision. In essence, the Council of State wants to prevent the case law from being frozen. This approach of the Council of State also reveals that although the case law is not as binding as the case-law consolidation decisions, it is a case law that is taken care to be followed and has a strong power to convince other courts/judges. Consant jurisprudence is thus explained as a product of the effort to ensure the integrity of case law rather than unifying it.