Does Failure To Object To An Expert Report Create A Vested Procedural Right?

1. Introduciton: Objections to Expert Reports and Vested Procedural Rights

An expert is a person whose opinion and assessment are sought in order to clarify a fact or allegation that is material to the resolution of a dispute and whose verification requires specialized or technical knowledge beyond legal expertise. The report prepared by the expert on the relevant matter is referred to as an expert report. Under Turkish civil procedure law, the expert report itself constitutes evidence.¹

Pursuant to Article 281 et seq. of the Turkish Code of Civil Procedure ("CCP"), the parties are required to submit their objections to the expert report, request a supplementary expert report, or seek the appointment of a new expert within two weeks from the date on which the expert report is served upon them.

The concept of a vested procedural right is defined in the decision forming the subject of this legal bulletin (the General Assembly of Civil Chambers of the Court of Cassation, dated 6 May 2026, File No. 2026/10-129, Decision No. 2026/299) as a right that arises in favor of one of the parties as a result of a procedural act carried out by either the court or the parties during the proceedings and that must be respected throughout the remainder of the litigation. Developed through the case law of the Court of Cassation to prevent unnecessary prolongation of proceedings, ensure legal certainty, and preserve confidence in judicial decisions, this doctrine has also gained broad acceptance in legal scholarship and has become one of the fundamental principles of Turkish civil procedure law.

In practice, divergent judicial decisions have emerged as to whether a party's failure to object to an expert report within the statutory time limit gives rise to a vested procedural right in favor of the opposing party with respect to the findings and calculation method set out in the report. This issue was also addressed by the General Assembly of Civil Chambers of the Court of Cassation in its recent decision dated 6 May 2026.

2. Divergent Approaches in Practice and Judicial Decisions

The legal consequences of failing to object to an expert report within the prescribed time limit have long been the subject of significant divergence in Turkish judicial practice, giving rise to conflicting judicial decisions.

Certain chambers of the Court of Cassation have held that, where a party fails to object to the initial expert report within the two-week period prescribed under Article 281 of the Turkish Code of Civil Procedure ("CCP"), the report becomes final with respect to that party. On this basis, they have taken the view that, in light of the principles of procedural stability and party disposition, such failure to object gives rise to a vested procedural right. By contrast, other chambers have adopted the view that this strict approach should be relaxed in order to ensure a fair trial and to establish the substantive truth. They have reasoned that, where an expert report is not suitable to serve as the basis of a judgment, requiring the court to resolve the dispute solely on the basis of that defective report would be incompatible not only with the relevant statutory provisions and the fundamental principles of procedural law, but also with the court's duty to ascertain the substantive truth. Accordingly, these chambers have concluded that a party's failure to object to an expert report does not give rise to a vested procedural right.

This issue has also been the subject of individual applications before the Constitutional Court. In its relevant judgment, the Constitutional Court held that the only right extinguished by a party's failure to carry out the procedural act of objecting to an expert report is the procedural right to object to that report itself. The Court further stated that interpreting this procedural rule as preventing a party from pursuing its substantive claim would amount to an unforeseeable interpretation of the rule. Accordingly, it concluded that a party's failure to object to an expert report does not give rise to a vested procedural right.

3. The Assessment of the General Assembly of Civil Chambers of the Court of Cassation

Against the backdrop of these conflicting lines of case law, the General Assembly of Civil Chambers of the Court of Cassation, in its decision dated 6 May 2026 File No. 2026/10-129, Decision No. 2026/299, emphasized the following key principles:

• Silence Does Not Constitute Implied Acceptance: A party's failure to object to an expert report within the prescribed time limit merely results in the loss of its procedural right to object to the report. Such silence cannot be construed as an implied declaration of intent amounting to the unconditional acceptance of the factual findings and technical assessments contained in the report. The General Assembly further emphasized that the expiry of a procedural time limit cannot be interpreted expansively so as to extinguish or restrict the parties' substantive rights, including their rights to claim receivables or compensation. Accordingly, in judicial proceedings, silence cannot produce legal consequences on the basis of the maxim that "silence implies admission.
• Expert Reports Constitute Discretionary Evidence: Under the framework of the Turkish Code of Civil Procedure ("CCP"), expert reports do not constitute conclusive evidence; rather, they are discretionary evidence and are therefore not binding on the court. Accordingly, even where the parties remain silent, the court may freely assess the expert report in its effort to ascertain the substantive truth and, where necessary, order a new expert report ex officio. The General Assembly of Civil Chambers further emphasized that the court's duty to establish the substantive truth continues even if neither party objects to the expert report. It expressly held that requiring a court to render its judgment on the basis of a defective or incomplete expert report would undermine the principles of judicial independence and adjudication based on the judge's conscientious conviction, as safeguarded under Article 138 of the Constitution.
• Substantive Rights Are Not Extinguished: A party's failure to object to an expert report, which is merely the non-observance of a procedural time limit, cannot be interpreted expansively so as to extinguish substantive rights, including rights to claim receivables or compensation. Accordingly, the claimant's failure to object to the expert report does not give rise to a vested procedural right in favor of the defendant.

BIBLIOGRAPHY: 1- Murat Atalı, İbrahim Ermenek, Ersin Erdoğan, Medeni Usul Hukuku, Ankara, Altıncı Baskı, 2023, 5.528

                                 2- General Assembly of Civil Chambers of the Court of Cassation, in its decision dated 6 May 2026 File No. 2026/10-129, Decision No. 2026/299, Court of Cassation, 9th Civil Chamber, dated 21 October 2025, File No. 2025/6895, Decision No. 2025/8147, Court of Cassation, 1st Civil Chamber, File No. 2024/4535, Decision No. 2025/811, 20 February 2025, Court of Cassation, 6th Civil Chamber, File No. 2021/4525, Decision No. 2021/1793, 25 November 2021, Court of Cassation, 10th Civil Chamber, File No. 2022/8856, Decision No. 2024/4525, 26 April 2024, Constitutional Court, Individual Application No. 2020/21347

Footnotes

^{1 (Murat Atalı, İbrahim Ermenek, Ersin Erdoğan, Medeni Usul Hukuku, Ankara, Altıncı Baskı, 2023, 5.528).}

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