Practical - Allows the researcher to openly take notes and record the information on events that they see.
Ethical - When compared to covertob , it avoids the problem of deceit and it allows the researcher to gain informed consent from those they are studying.
Theoretical - Due to openness of the researcher, allows them to check information, they can ask questions about events / meanings for actions (vaerstehen). Increase validity of data.
DISADVANTAGES
Practical - HAWTHORNE EFFECT - people are being watched, so they may behave in a certain way, the way you want them to behave. May affect validity of data.
Practical - Group being observed may only let the researcher see a limited amount of events, although this maybe beneficial it mans the researcher does not gain a true and accurate reflection.