Gravitational slip parameter as a function of scale as measured at 0.5 <z < 0.7 (top panel) and 0.7 <z < 1.2 (bottom panel). In both panels, the solid curves and associated shaded areas correspond to the expectations and 68% uncertainties for General Relativity in a ΛCDM background model set to TT+lowP+lensing Planck 2015 predictions (Planck Collaboration XIII 2016). In the top panel, the horizontal stripe shows the averaged over the range 3 h^-1 Mpc <r_p < 50 h^-1 Mpc obtained by Blake et al. (2016) at 0.43 <z < 0.7. E_G asymptotes to Ω_m/f in the standard model, and the simplest way of erasing the modest discrepancy with the model prediction would be to lower the density parameter.