“…In our study, the mean difference in a few domains turned out to be very small, even if it reached a statistically significant level when analyzed by Cohen's standard, and little evidence of systematic bias in the patient-proxy rating was found. In accordance with our results, past studies on patient-proxy difference in QoL measurement have found that the mean differences between two ratings are small and of questionable clinical meaning, suggesting that the benefit of using proxy responses [28,33].…”