DCE

[DanBo]

我想问一下，在使用SAS软件设计DCE时，如何添加约束，这样就不会出现两个不能组合在一起的关卡，只留下合理的组合？例如，有两个层次的会诊：线上会诊和线下会诊，核酸检测有两个层次：是和否。在线咨询只能与没有核酸检测相结合。SAS 中可以使用什么语法来实现此约束？

[ChrisNZ]

The quality of automatic translations these days never ceases to astonish me.

I would like to ask, when designing DCE with SAS software, how to add constraints so that there are no two levels that cannot be combined, leaving only reasonable combinations? For example, there are two levels of consultation: online consultation and offline consultation, and nucleic acid testing has two levels: yes and no. Online consultation can only be combined with the absence of nucleic acid testing. What syntax can be used in SAS to implement this constraint?