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. Author manuscript; available in PMC: 2020 Nov 1.
Published in final edited form as: Amyotroph Lateral Scler Frontotemporal Degener. 2019 Jul 23;20(7-8):576–583. doi: 10.1080/21678421.2019.1643375

Figure 1. Overview of ALS/SURV.

Figure 1.

ALS/SURV ranks and scores each participant, relative to all other participants, at the last observation in a visit window. Ranks are assigned from 1 (worst) to N (best) and can be performed at each visit window. Scores are ordered numerically and are calculated as follows: the participant’s rank (r) is divided by N+1 to bound the scores from 0 to 1. For a missed visit, ALSFRS-R can be interpolated if performed at the visits before and after. In this example, all participants can be scored at visit 1. At visit window 2, participants B, C, and D cannot be scored due to missing ALSFRS-R without a measure at the next time window; ALSFRS-R interpolation is performed for participants E and F; and participant’s A death is scored. At visit window 3, participants E, F, and G completed the study and participants’ A and D deaths are scored. The table shows scores and ranks of each participant at each window. Shaded cells indicate a carried forward rank due to the participant missing a visit window. Although this results in duplication of scores, it ensures that the ranks of completers are not skewed by withdrawing participants.