SPSS在计算组内相关系数ICC时出现warning，无法进行计算是什么原因？
两医师对某指标进行5分法等级评分，与研究两医师评分的一致性，故计算ICC，但是出现以下错误：
warning
Each of the following component variables has zero variance and is removed from the scale: TRAr1_acs
Too many items are deleted from the scale.
Execution of this command stops.