The nomothetic approach is considered scientific due to its’ precise measurement, prediction and control of behaviour, investigations of large groups, objective and controlled methods allowing for replication and generalisation. Due to this, it has helped psychology become more scientific by developing theories that can be empirically tested. Which is one of the key criteria of a science.
However the nomothetic approach does have its limitations. It has been accused of losing sight of the ‘whole person’, due to its extensive use of group averages. It also may give a superficial understanding, as people may display the same behaviour, but for different reasons. For example in the Milgrim study, can we be sure that all the behaviour displayed was for the same reasons?
Another limitation of this approach is that predictions can be made about groups, but not the individual. Telling someone that that they have a 3 in 100 chance of schizophrenia probably isn’t of much use to that individual.
There is also a potential underlying confounding variable with some of the research done following the nomothetic approach. Due to the extensive us of laboratory studies, the experiments often lack ecological validity, which means we cannot generalise the results to everyday life.