GRADE（Grades of Recommendation, Assessment, Development，and Evaluation）方法为卫生保健中的证据质量评价与推荐强度评级提供指导。对那些为系统评价、卫生技术评估及临床实践指南总结证据的人而言，GRADE具有重要意义。GRADE提供了一个系统而透明的框架用以明确问题，确定所关注的结局，总结针对某问题的证据，以及从证据到形成推荐或作出决策。GRADE方法的广泛传播与应用，获全球50余个组织认可，这些组织大多有很强的影响力（http://www.gradeworkinggroup.org/），足以证明该工作的重要性。本文介绍临床流行病学杂志将刊出的20篇系列文章，为如何使用GRADE方法提供指导。
本文是GRADE（Grading of Recommendations Assessment，Development，and Evaluation）系列文章的导论。该系列文章为使用GRADE系统提供指导，介绍如何将该系统用于系统评价、卫生技术评估（HTAs）及临床实践指南中备选方案的证据质量评价和推荐强度评级。GRADE方法始于提出一个明晰的问题，包括对所有重要结果的详细说明。证据被收集和汇总后，GRADE提供了明确的标准来评价其质量，包括研究设计、偏倚风险、不精确性、不一致性、间接性及效应量大小。
Evidence is the core of Evidence-Based Medcine; the Grades of Recommendations Assessment, Development and Evaluation (GRADE System) is a milestone in the history of evidence development. This paper outlines the GRADE System and GRADEpro 3.2 software, and briefly explores the right and wrong application which was published in the Chinese Journal of Evidence-Based Medicine. The GRADEpro 3.2 software is easy to operate, but for evaluating the reasons of upgrade and downgrade, and the importance of the parameters of outcomes, it needs to comprehensively and systematically understand the knowledge of relevant background, and to construct a solid foundation in clinical epidemiology and systematic review. In view of this paper based on the current GRADE System, there may be some discrepancy to the later content with the GRADE System constant improvement. Therefore, it is bly recommended that readers should keep constant learning and improving.
A systematic literature search and a comparative study were conducted to investigate the evolution of the levels of evidence and strength of recommendations in medical research. Fifty systems were included from 1979 to 2007, and 11 of these, which came from five states or international organizations, were selected and divided into three stages according to their characteristics, sphere of influence and application fields. Ideas about levels of evidence and strength of recommendations are becoming mature in medical research. The challenge for the future is how to introduce evidence-based principles and develop the corresponding levels of evidence and strength of recommendations in the fields of management, education, basic medical sciences, economics, sociology and legal research.
Evidence grading and recommendation strength assessment are key steps in the development of evidence-based guidelines, and have made significant progress in recent years. This article systematically reviews the development and evolution of evidence grading and recommendation strength in the past 30 years, and introduces the main representative standards. At the same time, a brief introduction is given to the guidelines and consensus evaluation results published in the field of neurological diseases in China, and future improvements are proposed. This article aims to help readers understand the development patterns of evidence grading and recommendation strength, in order to better understand the guidelines, and to develop more standardized guidelines.