Chat about Novel Coronavirus - 2019-nCoV - COVID-19

Maybe I'm mis-interpreting the findings, but do they take into account whether the the rest of the public (not involved in the study) were also wearing a mask? As far as I'm aware, masks are recommended to stop an individual spreading the virus to others when they exhale, rather than stopping them catching it from others when they inhale.

Edit: should've read further.

Here, we report a randomized controlled trial (20) that assessed whether a recommendation to wear a surgical mask when outside the home among others reduced wearers' risk for SARS-CoV-2 infection in a setting where public health measures were in effect but community mask wearing was uncommon and not recommended.

I guess it still doesn't answer the question of how effective it is if everyone wears masks though.