-GENERALISABILITY: poor, 38% deselected after screening, may have lead to lower obedience levels-RELIABILITY + VALIDITY: none knew Milgrams research, excluded if took 2+ psychology classes, enhanced internal validity of study-APPLICATION: limited to real world, situation lost potency because ppts were stopped before any real distress-ETHICS: meticulous safeguards, very safe, little mental damage, ppts screened BUT ppts didnt know, withheld info so still unethical