Reduced chi-squared statistics of the power spectrum. If this quantity is close to one, the power spectrum of the given method is consistent with the PF method. While the original simulation becomes inconsistent with the cosmic average power spectrum at late times, the average power spectrum of the PM and O–C simulations is a good match to the PF results. We used all available k ≤ 1.5 Mpc h⁻¹ modes when we calculated these functions.