The lensing rate, defined as the ratio of the number of observable lenses to the parent ETGs used to simulate them, is plotted as a function of velocity dispersion. Solid lines in the left and right panels represent results from our Monte Carlo simulations for single-source and double-source strong lensing, respectively. The dashed line in the right panel corresponds to a ‘pseudo’ double-source lensing rate obtained by squaring the curve from the left panel. The solid line in the right panel exhibits a counter-trend drop in the largest velocity dispersion bin due to significant Poisson counting noise.