Brockington 1978.

Study characteristics
Patient sampling	Retrospective, unclear patient selection.
Patient characteristics and setting	N included in study: 134. N in analysis: 134. Age: Not reported. Gender: Not reported. Ethnicity: Not reported. Comorbid disorders: Not reported. Duration of symptoms: Not reported. Concurrent medications used: Not reported. Inclusion criteria: Diagnosis of functional psychosis (schizophrenia, affective psychosis, paranoid state, or other/unspecified psychosis). Exclusion criteria: Children under 15 years, geriatric patients over 65 years and people suffering from addictions, neuroses or situational disturbances. Study aim: Compare 10 definitions of schizophrenia in respect of their reliability, concordance and prediction of outcome with two different samples of patients. Previous treatment for schizophrenia: Not reported. Clinical setting: Inpatients. Country: UK.
Index tests	Description of FRS used: The symptoms of first rank importance are: Audible thoughts, voices heard arguing, voices commenting on one's actions; the experience of influences playing on the body (somatic passivity experiences), thought withdrawal and other interferences with thought; diffusion of thought, delusional perception and all feelings, impulses (drives) and volitional acts that are experienced by the patient as the work or influence of others". Professionals performing test: Psychiatrists. Resolution of discrepancies: "Disagreements were resolved and an agreed verdict reached, so that, for each definition, each patient had a diagnosis made (schizophrenia present or absent) by agreement between 2 raters". How FRS used in study: Diagnosis.
Target condition and reference standard(s)	Reference standard: Final diagnosis comprised of original history, mental state schedules and follow‐up data reviewed to give a 'final' or lifetime' diagnosis. Target condition(s): Schizophrenia and non‐schizophrenia. Professionals performing test: 2 Psychiatrists. Resolution of discrepancies: Two raters worked together to decide on final diagnosis.
Flow and timing	Study process: A sample of mixed first and subsequent admissions interviewed by the US/UK diagnostic team at that hospital and given a project diagnosis of some form of functional psychosis (schizophrenia, affective psychosis, paranoid state, or other/unspecified psychosis). The interviews, using the 7th edition of the Present State Examination, were carried out usually within 24 hours and always within 72 hours of admission. 12 diagnostic definitions* were applied by 2 raters working independently from observations made at a single mental state examination. Follow‐up interviews were done an average of 6.5 years after the index admission, and final diagnoses were made by 2 raters based on original history, mental state schedules and follow‐up data . Follow‐up: 6.5 years
Comparative
Notes	2 samples were reported (Camberwell and Netherne), however we only refer to the Netherne sample since this is the only one to report the reference standard of 'final diagnosis'.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
		Unclear	Low
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
Did the study pre‐specify whether they were using one or multiple FRSs?	No
		Unclear	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	No
		Unclear	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	No
Were all patients included in the analysis?	Yes
Did all patients receive a reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Did all patients receive an index test?	Yes
Did all patients receive the same index test?	Yes
		Low