Fig. 2From: Prospective multicentre validation study of a new standardised version of the 400-point hand assessmentBland Altman method for intra-rater and inter-rater reliability. Intra-rater and inter-rater reliability with the Bland–Altman method. The middle. Line represents the mean difference between the two tests. The upper and lower lines represent the upper and lower limits of agreement, i.e. mean difference +/− 1.96 SD of the differences respectivelyBack to article page