Test-Retest: r=0.82 (Gouvier et al. 1987).

Interobserver Reliability: average r=0.89 (Gouvier et al. 1987); r=0.84, overall reliability index=0.91, κ=0.31 (Beauchamp et al. 2001) (ABI).

Concurrent Validity: LCFS ratings correlated with Stover & Zeiger ratings at admission (r=0.92) and discharge from rehabilitation (r=0.73). Discharge LCFS ratings also correlated significantly with discharge Glasgow Outcome Scale (GOS) scores (0.76) and expanded GOS scores (0.79) (Gouvier et al. 1987). LCFS ratings and scores on the functional cognition index (FCI) correlated at admission (r=0.79) and discharge (r=0.77) from inpatient rehabilitation (Labi et al. 1998; TBI); GCS and LCFS ratings significantly correlated (r=0.329, p<0.05) (Hall et al. 1993; TBI).

Construct Validity (Known Groups): LCFS ratings could discriminate between groups based on categories of vocational recommendations (return to work, vocational training, supported work and continued remedial therapy; p<0.0001). LCFS ratings accounted for 51% variance between cell means (Mysiw et al. 1989) (TBI).

Predictive Validity: Initial LCFS ratings correlated with Stover & Zeiger ratings (0.65), GOS (r=0.57) and E-GOS (0.73) scores collected at the time of discharge from rehabilitation (Gouvier et al. 1987). LCFS at admission to and discharge from rehabilitation as well as LCFS change scores were significantly associated with employment status at one year post-injury (Cifu at al. 1997; TBI). Initial and discharge LCFS ratings significantly related to vocational status up to 26 months post injury (Rao & Kilgore, 1997; TBI).