Bland-Altman plots of the HRQOLISP-26 versus HRQOLISP-63 (Berlin). Bland-Altman plots of the differences between the 63-item physical sphere of the HRQOLISP (initial) and the HRQOLISP-26 (shorter) scores related to the mean of the HRQOLISP-63 and HRQOLISP-26 scores for domains and total score in Berlin. The -axes represent levels of HRQOL calculated as the means of the initial and shorter version scores and the -axes represent the differences between scores on initial and shorter versions. The horizontal lines represent the mean difference.