Signal-to-noise ratio versus the logarithm of the ratio of total to peak fluxes for the LOFAR sample of 36 631 sources. S/N is calculated here by dividing the total radio flux by its associated error. Sources classified as compact are shown in black, complex ones in light grey. The light red curve is taken from Shimwell et al. (2022, Eq. (2)), below which 99.9% of all compact or unresolved sources lie.