+High levels of control: Asch controlled response of confederates and the task so made it easier to see when people conformed and measure how may people conformed.
+standardised: allows for replication and can asses the reliability.
-Low mundane realism: the task isn't something you wo0uld perform in everyday life - doesn't reflect real life.
-Demand characteristics: people may have questioned why everyone was getting an easy answer wrong. They may figure out the aim.