Top: scatter plot of Kepler exoplanets, separated by the line ﹩{R}_{\mathrm{trans}}/{R}_{\oplus }=1.05\,{(F/{F}_{\oplus })}^{0.11}﹩ (left) or ﹩{R}_{\mathrm{trans}}/{R}_{\oplus }=2.6\,{(P/\mathrm{yr})}^{-0.1467}﹩ (right). Bottom: cumulative distribution of size ratios (R_out/R_in). Planet pairs that are entirely above (blue) or entirely below (red) R_trans have similar radii. But when the planets straddle the line, the outer planet is typically significantly larger than the inner planet.