reliability and validity of diagnosis Flashcards
how do you measure reliability of diagnosis?
two clinicians agreeing on the same diagnosis for the same disorder based on different diagnostic tools.
what are the two measurements of reliability?
cohen’s Kappa: a scale from 0-1 (0 being no agreement between psychiatrists and 1 being total agreement.)
PPV = proportion of people who when being re-assesed on their diagnosis get the same diagnosis over a period of time.
what did cooper find?
cooper found that new york psychiatrists were twice as likely to diagnose someone with schizophrenia and london psychiatrists were twice as likely to diagnose someone with depression and mania when watching the same clip of a paitent interveiw.
what did beck find?
beck found that the agreement between to clinicians on 153 patients was only 54% due to vague criterea and different methods of gathering data.
what did di nardo find?
he found that when testing the reliability of the dsm 3 using the cohen kappa scale, when two clinicians seperately diagnosed 276 patients with anxiety and stress disorders. he found that obsessive compulsive disorder had a rating of 0.80 (high) whereas generalised anxiety disorder had a rating of only 0.57. this was thought to be due to personality disorders having overlapping symptoms making them hard to distinguish.
what did goldstein find?
he found that when looking back at cases of patients and their diagnosis, was agreed by experts suggesting high reliability.
