Radial properties across the ARKS sample. Linear models were fitted in linear or log space (as appropriate for the way the data in each panel are plotted) and displayed as dotted lines. The significance is evaluated as the ratio of the slope to its uncertainties, as displayed in the upper right corner of each panel. In panels a and c, the linear model shown is that fitted to single-ring discs only, whereas in panels b and d, the line is fitted to all points. In panel b, the dash-dotted line has a slope of 6/23, as predicted for self-stirred discs (Kennedy & Wyatt 2010). In panel d, the dashed line indicates where the fractional inner and outer edge widths are equal. The width of an edge is defined as the number of au for the radial profile to rise (fall) from 25 (75%) to 75% (25%) of the peak, and the radius of an edge is defined as where the radial profiles crosses 5 0% of the peak.