The authors argue that despite recalculations and different inclusion criteria, the minimally important difference in health-related quality of life scores remains close to half a standard deviation.
In this issue of Expert Review of Pharmacoeconomics and Outcomes Research, Farivar, Liu, and Hays present their findings in 'Another look at the half standard deviation estimate of the minimally important difference in health-related quality of life scores (hereafter referred to as 'Another look') . These researchers have re-examined the May 2003 Medical Care article 'Interpretation of changes in health-related quality of life: the remarkable universality of half a standard deviation' (hereafter referred to as 'Remarkable') in the hope of supporting their hypothesis that the minimally important difference in health-related quality of life measures is undoubtedly closer to 0.3 standard deviations than 0.5. Nonetheless, despite their extensive wranglings with the exclusion of many articles that we included in our review; the inclusion of articles that we did not include in our review; and the recalculation of effect sizes using the absolute value of the mean differences, in our opinion, the results of the 'Another look' article confirm the same findings in the 'Remarkable' paper.
Norman et al. (Fri,) conducted a editorial in Health-related quality of life. Half a standard deviation estimate vs. 0.3 standard deviations was evaluated on Minimally important difference in health-related quality of life scores. The authors argue that despite recalculations and different inclusion criteria, the minimally important difference in health-related quality of life scores remains close to half a standard deviation.