Total number of questions
Age 6-13 = parent report, age 14-17 = self-report
Scoring and interpretation
Reliability and validity
Test/retest reliability of the PSC ranges from r = .84 - .91. Over time, case/not case classification ranges from 83%-87% and kappa = .84 (Jellinek et al. 1988; Murphy et al. 1992). Studies (Murphy & Jellinek 1988; Murphy et al. 1996) indicate strong internal consistency of the PSC items (Cronbach alpha = .91) and highly significant (p < 0.001) correlations between individual PSC items and positive PSC screening scores.