Size-mass relations and size deviations of GRB hosts from star-forming galaxies. Top panels: half-light radius against stellar mass for GRB hosts and star-forming galaxies at 1 < z < 2 (left panel) and 2 < z < 3.1 (right panel). The GRB host galaxies are displayed as red circles and the 3D-HST star-forming galaxies are shown as gray circles with an area proportional to their SFR. The median of the star-forming population is shown as a dashed gray line. The dashed cyan line represents the expected median of a GRB hosts population that does not suffer from bias to trace the SFR (gray circles weighted by their SFR). The 1σ uncertainty of the cyan median is given as a shaded cyan region. The vertical dashed black line is the mass-completeness limit of the 3D-HST survey. Bottom panels: cumulative distribution of Δ(R_e − M_∗) at 1 < z < 2 (left panel) and 2 < z < 3.1 (right panel). The Δ(R_e − M_∗) represents the distance between GRB hosts and the SFR-weighted R_e − M_∗ relation of the top panels. The blue curve is a Gaussian CDF with a mean of 0 and a standard deviation defined by the 1σ errors of the shaded cyan area at the GRB hosts positions. The p-value returned by the two-sided K–S test is provided in the right bottom part of panels.