Background <p>Colorectal cancer (CRC) is one of the most prevalent cancers globally, and its treatment has garnered significant attention. The promotion and application of the Enhanced Recovery After Surgery (ERAS) concept have notably reduced postoperative hospital stay durations for CRC patients and improved recovery efficiency. However, there exist significant discrepancies in the discharge criteria for CRC patients, with a lack of uniformity and specificity in the evaluation standards for postoperative hospital days across different regions and healthcare institutions. This has led to the widespread issue of ineffective hospital day (IHD) post-surgery. IHD not only increases the medical costs for patients but may also pose potential threats to their health, thereby affecting the overall treatment outcomes. Therefore, establishing a set of scientific, reasonable, and highly targeted evaluation standards for postoperative hospital days in CRC is of paramount importance for optimizing the utilization of medical resources and facilitating the rapid and safe recovery of patients.</p> Objective <p>Based on the Appropriateness Evaluation Protocol (AEP) framework, an evaluation index system for IHD after colorectal cancer surgery has been developed within the framework of ERAS. This system aims to guide early and safe discharge of colorectal cancer patients postoperatively, effectively reduce hospitalisation costs, and promote rational conservation of medical resources.</p> Methods <p>Under the guidance of AEP framework, an initial draft of the evaluation index system for ineffective hospital days following colorectal cancer surgery in the context of ERAS was first constructed through a literature review and in-depth discussions among the research team. Subsequently, experts in the field were invited to participate in two rounds of Delphi expert consultations. After comprehensive analysis and synthesis of the experts’ opinions, the final index system was established, and weight calculations for each index were conducted.</p> Results <p>The response rate for the two rounds of expert consultations reached 100%. The expert authority coefficients were 0.903 and 0.918, with variation coefficients ranging from 0.070 to 0.225 and 0 to 0.135, respectively. The Kendall harmony coefficients were 0.397 and 0.291. The final indicator system for postoperative ineffective hospital days in colorectal cancer patients established under the ERAS framework includes 4 indicators for medical services, 4 indicators for nursing/life support services, and 7 indicators for patient condition factors.</p> Conclusion <p>The evaluation index system for ineffective hospital days in postoperative colorectal cancer patients, constructed based on AEP standards within the context of ERAS, demonstrates both scientific rigor and practical applicability. It holds significant reference value for guiding the discharge of colorectal cancer patients postoperatively and promoting early and safe discharge.</p>