Label agreement for different numbers of atlases and labels per voxel. The data of Figure 6 are broken up here into subsets of voxels according to the number of different atlas labels assigned to each voxel. Voxel populations with fewer label assignments (greater agreement between the atlases) have higher label agreements with manual labels. Therefore, the number of labels per voxel provides a rough confidence measure for each voxel's label. The error bars extend one standard deviation about the mean. Remaining data for voxels with five or more labels are not included for clarity.