The second insight concerns the choice of noise modelling. Despite the fact that SNR at b=0 and T E=152 ms falls to about 6, use of the Rician noise model does not appear to be a significant benefit in predicting unseen signal; here, however, we do not investigate the effect on estimated model parameters, which may still benefit from the more accurate noise model. In this challenge, most participants used non‐linear least‐squares or maximum‐likelihood optimization. Additional regularization of the objective function (Eufracio & Rivera/Lasso, Rokem/Elastic Net, Fick/Laplacian) appeared to have little benefit over non‐regularized optimization.