R₁ as a function of galaxy stellar mass over redshift for all the galaxies in our sample, where the stellar mass is measured within 20% of R₂₀₀. The left-hand panel shows the median value of the galaxy size, measured using the R₁ criteria, for all simulations. Each colour represents a different redshift, from z = 0 (in blue) to z = 1 (in yellow). The median value of the size has been measured within 20 stellar mass bins in each case. We also show the 1σ error as shaded regions. The right-hand panel shows a normalised histogram of the scatter between each singular size value and its corresponding bin value, $\overline{R}$, for z = 0.0, z = 0.5, and z = 1 in blue, grey, and yellow, respectively. In every case, the global σ of the relation was found by fitting a Gaussian distribution (solid line following the same colour as the respective histogram). The respective σ was defined as the standard deviation of the respective Gaussian distribution, whose errors were computed via bootstrapping.