“效度”原是计量学中的一个重要概念,文章借用该术语来探讨汉语方言语法比较研究如何提高其有效程度的问题。文章指出,“准确度”与“深度”这两个因素直接影响着比较研究效度的高低,必须注意在这两方面上下功夫。只有这样,方言语法比较研究才能真正达到其目的,并使研究成果具有更高的价值。 “Validity” was originally an important concept in metrology. The article borrowed the term to discuss how to improve the validity of the comparative study of grammar of Chinese dialects. The article points out that the two factors of “accuracy” and “depth” have a direct impact on the validity of comparative research. We must pay attention to these two aspects. Only in this way can the comparative study of dialect grammar really reach its goal and make the research results have higher value.