Box plots of error rates for dichotomizing at cut-point of mRS 1 (mRS 0–1, 2–6), trichotomizing at cut-points 1 and 4 (mRS 0–1, 2–4, 5–6), dichotomizing at mRS 2 (mRS 0–2, 3–6), and trichotomizing at cut-points 2 and 4 (mRS 0–2, 3–4, 5–6).

<p>van Swieten’s inter-rater reliability matrix used as confusion matrix. Post-hoc testing shows that both trichotomization errors are higher than dichotomization (p<.05).</p

Box plots of error rates for the full ordinal scale of mRS (mRS 0.6), considering mRS 0 to 3 as individual grades and collapsing mRS grades 4 to 6 (mRS 0.3,4–6), dichotomizing at various cut-points of mRS 1 (mRS 0–1, 2–6), mRS 2 (mRS 0–2, 3–6), mRS 3 (mRS 0–3, 4–6) and mRS 4 (mRS 0–4, 5–6).

<p>van Swieten’s inter-rater reliability matrix used as confusion matrix. (p<.001 ANOVA; post-hoc testing shows that all dichotomization errors are lower than either full scale errors with mRS 0–4 dichotomization the lowest; p<.05).</p

Error percentages for 38 studies for the full ordinal scale (mRS 0.6), partially collapsed ordinal scale (mRS 0.3, 4–6) and dichotomization (mRS 0–1, 2–6; mRS 0–2, 3–6; mRS 0–3, 4–6; mRS 0–4, 5–6) and trichotomization (mRS 0–1, 2–4, 5–6; mRS 0–2, 3–4, 5–6) cut-points.

<p>Error percentages for 38 studies for the full ordinal scale (mRS 0.6), partially collapsed ordinal scale (mRS 0.3, 4–6) and dichotomization (mRS 0–1, 2–6; mRS 0–2, 3–6; mRS 0–3, 4–6; mRS 0–4, 5–6) and trichotomization (mRS 0–1, 2–4, 5–6; mRS 0–2, 3–4, 5–6) cut-points.</p

Shannon’s information transmission model adapted to scoring of a patient on the 7 point modified Rankin Scale.

<p>A noise or error source is assumed to be in the channel between the sender represented by the ‘True Rankin’ score and the receiver represented by the ‘Observed Rankin’ score.</p

Inter-rater reliability matrix for mRS from Wilson et al [26] used as confusion matrix.

<p>Box plots of error rates for the full ordinal scale of mRS (mRS 0.6), considering mRS 0 to 3 as individual grades and collapsing mRS grades 4 to 6 (mRS 0.3,4–6), dichotomizing at a cut-point of mRS 1 (mRS 0–1, 2–6), dichotomizing at a cut-point of mRS 2 (mRS 0–2, 3–6), mRS 3 (mRS 0–3, 4–6) and mRS 4 (mRS 0–4, 5–6). Post-hoc testing shows that each error rate with this matrix is higher than the corresponding error using van Swieten’s confusion matrix except the error rates for mRS 4.</p