目前，减少无效住院日是改善医疗服务质量、提高工作效率的重要途径。然而，现有的国内研究并未形成无效住院的标准定义，多数学者根据自身经验和主观判断给出无效住院的定义和评判标准，信度和效度并未得到检验，方法的科学性和规范性、结果的真实性遭到质疑，很难有效指导后续的研究与实践。本研究以美国开发的入院及住院日适宜性评价体系(AEP)及其衍生版本为基础，根据"The Delay Tool"原因分析工具，参考相关研究，并结合我国病种和科室的分类情况，研制开发一套适合我国国情的无效住院综合评价体系。弥补我国在无效住院研究上的理论方法不足、为提高医院服务效率、改善医疗服务质量提供科学依据。研究分理论研究、体系开发和实证研究三部分，以上海交通大学医学院附属三级医院为样本，从妇科、神经外科、心血管内科、血液内科筛选研究病例，进行无效住院存在状况、主要影响因素和产生原因的分析，进而有针对性地给出政策建议。

Nowadays, it is to decrease the unnecessary hospital stays that is a significant channel to improve the quality of medical service and to raise the working efficiency. However, there has not been formulated the generalized conceptions in the available domestic studies, and many scholars base on their own clinical experience and objective judgments to outline defining criteria, so that it is questionable of the standardability of methodologies and the reliability of outcomes. It is considered that the current studies could not lay the foundations for the further theoretical and empirical researches. This research would develop a comprehensive assessment system, China Unnecessary Hospitalization Assessment System. Based on the original American Appropriateness Evaluation Protocol (AEP) and its modified versions, the CUHAS considers 'The Delay Tool', the relevant studies and the disease and department classification in China as reference, hoping to make up the theoretical and methodological deficiency of unnecessary hospitalization and to supply the scientific supports for improvements of hospitals' service efficiency and quality. This research is divided into three parts, namely theoretical research, system development and empirical research, and would select the medical records of patients from the gynecology, neurosurgery, vasculocardiology departments, and haemal internal medicine in the Tertiary hospitals affiliated to Shanghai Jiaotong University School of medicine, for the sake of analyzing the prevalence, factors and reasons of unnecessary hospitalization. Ultimately, this research would make the targeted suggestions for the subject matters.