Measurement inconsistency arises from a variety of causes, most of which occur only occasionally, if at all, in short-term or experimental studies but are almost inevitable in long-term studies.

• 测量的不一致性因多种原因而产生。其中大多数即使出现，也只是在短期或实验室中偶然出现，但是在长期实验中不可避免。