Combined fit of the mass-concentration relation, using the results from the stacks in velocity dispersion (open-blue squares, weak-lensing alone) and the values derived by Oguri et al. (2012; red triangles) and Umetsu et al. (2011a; open-green triangle) from the stacked analysis of strong-lensing galaxy clusters. The best-fit relation was obtained assuming a scaling in redshift of (1 + z)^-0.45, and the black solid line show the results for z = 0.5 (the gray-shaded area delimits the statistical uncertainty from the best-fit parameters). Overplotted are the relations derived from numerical simulations by Duffy et al. (2008; black-dashed line, all haloes, z = 0.5) and Meneghetti et al. (2014; orange-solid line, strong-lensing selected haloes, z = 0.5). The magenta-dashed lines show the 1σ limit around the average relation derived by Oguri et al. (2012) from semi-analytical predictions (lensing bias using weights from the arc cross section+Einstein radii, z = 0.45).