all the participants were women - not generalisable
lacks mundane realism and population validity
artificial task which lacks ecological valididty
deceived his participants so didn't gain fully informed consent, but if he had they may have displayed demand characteristics
majorities are more powerful than minorities and minority influence in this case does not reflect the complexity of real-life minority influence of contrived situations - results may be limited in terms of real world applications
in a variation, they wrote down their answers privately rather than publicly saying them after being exposed to the confederate's views
participants agreement with the minority was then greater, suggesting they had been converted