@WesPegden @dave_andersen We don't know the magnitude of what would happen in the SAME situation without masks.
e.g. hypothetical
w/masks in mandate location = case rates X
w/o masks in mandate location = case rates 10X
w/o masks somewhere else, case rates = X
= no conclusion
@WesPegden@dave_andersen我们不知道在没有面具的情况下会发生什么。
e、 g.假设的
任务地点带口罩=病例率X
任务地点不带口罩=病例率10倍
其他地方没有口罩，病例率=X
=没有结论