Comparison of the outflow properties for LyC leakers (red symbols) and the control sample (blue squares). The upper left panel gives the relationship between the Si ii equivalent width and Si iii equivalent width. The upper right panel shows the variation of the Si ii equivalent width with the Si ii velocity at 90% of the continuum (v₉₀). The bottom left panel compares the v₉₀ of the Si ii and Si iii transitions. The bottom right panel compares the equivalent width weighted velocity of the Si ii line (v_cen) to the Si iiv₉₀. Black lines mark one-to-one relationships. The black crosses in all panels indicate the typical uncertainties for the control sample. Note that we only measure LyC upper-limits for the Leitherer et al. (2016) sample (red diamonds; see the Appendix).