inextricably linked cause a diagnosis cannot be valid if not reliable 

inter-rater (2 assessors give similar diagnosis) & test-retest (consistent over time), DSM 

Copeland-69US,2UK, Lehman playful v harsh voices 

the extent that a diagnosis represents something that is real and that a classification system measures what its meant too 

Boverman- woman=mentally unhealthy, Loring&Powell 290, 56, 20

ppl with schiz have symptoms to be diagnosed with other diagnosis, depression 

2 or more conditions co-occuring, Buckley- depression 50%, substance abuse- 47% 

DSM not routinely used with H reliability, Whaley-+11, lacks objective measures

50 USP asked to differentiate bizarre and non-bizarre, inter-rater reliability of .40 

Brekke&Barrio, Non-whites= less, minorities better protective characteristics and social structures 

ppl with DID show more schizophrenia symptoms then ppl diagnosed with schiz, challenging validity 

Weber, 6 million, schiz patients had medical problems, received lower standard of care