Variability in the subscale Activities of Daily Living of the Knee injury and Osteoarthritis Outcome Score (KOOS) over two years. Subjects are divided into three groups (tertiles) according to their age. Each line represents one individual visualizing the difference between the score in 1998 (presented as zero, left endpoint of line) and in 2000 (right endpoint of the same line).
Paradowski et al. Health and Quality of Life Outcomes 2005 3:59 doi:10.1186/1477-7525-3-59