Comparison of different RV models, including subsets of the HIP 41378 planets, ranked by their expected log point-wise predictive density (elpd LOO). Each model label indicates the included planets and, for planet d, the tested orbital period in days. Higher elpd LOO values correspond to better out-of-sample predictive performance. The horizontal line segments represent the standard error of the elpd. The lighter line segment with triangles indicates the elpd difference of one model relative to the best model.