Evaluating the FONE FIM: Part II. Concurrent validity & influencing factors.
The "motor" (activities of daily living) component of the FONE FIM, the telephone version of the Functional Independence Measure (FIM) was evaluated in a cohort of 132 patients who had been discharged to home from a geriatric inpatient assessment and rehabilitation program. In the current study, Rasch person ability measures were derived from telephone assessments 5 weeks after discharge and in-home assessments 1 week later. Concordance between the modes was shown to be satisfactory for the Rasch measures based on intraclass correlation coefficients. However, the telephone mode consistently generated lower estimates than did the observational mode. This was due to the fact that the telephone mode underestimated motor function for the majority of patients who were at higher levels of cognition and motor function, but overestimated for patients who were at lower levels of cognition and motor function. At the item level, concordance, as determined by Kappa statistics, was better when the FONE FIM responses came from the patient rather than proxy respondents, and when the assessments were done by more experienced rather than less experienced raters. Based on these findings, a mixed strategy, the telephone mode for patients capable of responding to the FONE FIM and in-home assessments for those who are incapable, is recommended.