Background. The success of large scale surveys depends on well designed questionnaires and the
skills of lay interviewers. Discrepancies in prevalence rates between epidemiological surveys and
poor agreement between survey interviewer and clinician diagnostic interviews are giving rise to
increasing concern among researchers, public health planners and policy developers. New
approaches to information collection are called for. The feasibility of training experienced survey
interviewers in semi-structured, clinical, diagnostic interviewing has never been investigated
systematically across the range of neurotic and psychotic disorders.
Methods. Eight experienced survey interviewers from the Office for National Statistics (ONS) were
selected and underwent extended training in a Survey Form of SCAN (SCAN-SF). Sixty-four
adults, including a majority of psychiatric in-patients were assessed by ONS interviewers and re-interviewed within a week by SCAN-trained clinicians. Feedback was sought from interviewers and
Results. Trainers found lay interviewers coped at least as well with psychotic as with neurotic
symptoms. Concordance for any disorder was 0·74 (95% CI: 0·57 to 0·91); for any specific psychotic
disorder 0·63 (0·40 to 0·86); for any specific neurotic disorder 0·63 (0·43 to 0·83). Sensitivity ranged
from 0·6 to 0·9 and specificity from 0·8 to 0·9. There was no evidence of rater bias.
Conclusions. These preliminary findings are very promising. However, before the SCAN-SF,
administered by carefully trained lay interviewers, can be recommended in large scale surveys,
further evaluations of its feasibility and reliability in the general population are needed.