Average completeness of companion search as a function of semi-major axis a (left panel) and mass ratio q (right panel). The upper panel is for stellar companions alone (0.05 < q < 1); the lower panel is computed over the whole range of separations considered in this paper (−2 < log a/au < 4). In both panels, the solid line is for Ursa Major, the dotted line is for Coma Berenices, and the dashed line is for Hyades.