Reliability of the life chart schedule for assessment of the long-term course of schizophrenia

We report on the inter-rater reliability of the Life Chart Schedule (LCS). The LCS is designed to assess the long-term course of schizophrenia in four key domains (symptoms, treatment, residence, and work) over two time periods (past two years, entire period of illness). The subjects were 27 consecutive admissions to a schizophrenia research unit. The LCS was filled out by pairs of raters, blinded to each others' ratings, using the same data (interview with subject and chart). Reliability was examined for 45 LCS ratings selected from all four domains and both time periods. Selected ratings pertained to the duration of specified experiences, the quality of these experiences, and the long-term time trend. The kappa statistic and the intra-class correlation coefficient (ICC) were used to determine inter-rater reliability for continuous and categorical ratings, respectively. LCS ratings proved reliable in all four key domains and both time periods. The reliability was fair to excellent for ratings of duration of experience (ICC ranged from 0.53 to 0.99), quality of experience (kappa ranged from 0.46 to 0. 92) and long-term time trends (kappa ranged from 0.66 to 0.94). The LCS can be used to obtain reliable ratings of the long-term course of schizophrenia in multiple domains.