And you might say, well, why is that important? Well, if the physician knows it might, or the person administering or interfacing with the patient, they might give a tell somehow. They might not put as much emphasis on the importance of taking the pill if it's a placebo. They might by accident give away some type of information. So to avoid that type of thing happening, you would have a, you could do a double blind. And there's even, some people talk about a triple blind experiment where even the people analyzing the data don't know which group was the control group and which group was the treatment group. And once again, that's another way to avoid bias.