Introduction: Since its translation into Chinese, the Functional Living Index for Cancer (FLIC) has not been widely received due to some of its difficulties. We modified its visual analogue scale (VAS) to an ordered categorical scale and changed some of the wording in the instrument. This study examined the measurement properties of the modified FLIC.
Materials and methods: The modified version of FLIC and the Functional Assessment of Cancer Therapy (FACT-G Chinese version 4) were filled in by 140 patients recruited from the National Cancer Centre Singapore. The patients' FLIC scores were compared with their clinical characteristics to establish known-group validity. Convergent and divergent validity of FLIC were examined by correlation analysis with FACT-G and its sub-scales. Cronbach's alpha and relative efficiency were also examined.
Results: FLIC and most of its sub-scales could indicate a clear and statistically significant difference of quality of life (QOL) according to patients' performance status and treatment status. FLIC strongly correlated with FACT-G. The Physical, Psychological, and Symptoms sub-scales of FLIC converged to and diverged from FACT-G sub-scales as conceptually expected. Cronbach's alpha indicated a satisfactory level of reliability. FLIC appeared to be more efficient than FACT-G, meaning that a smaller sample size will be required for FLIC than for FACT-G to achieve the same research purpose.
Conclusions: The modified version of FLIC was found to have achieved satisfactory measurement properties. This is a user-friendly alternative to the original FLIC.