On negative Cronbach alpha coefficient and split-half reliability coefficient
论负克伦巴赫alpha系数和分半信度系数

This paper discusses the phenomena of negative reliability, pointing out that when Cronbach alpha coefficient or split-half reliability coefficient is negative, the prototype formulae for Cronbach alpha and the SpearmanBrown prophecy formula will become invalid. The paper analyzes the cause of the phenomena and their respective substitutes in this case.