\begin{tabular}{ll c cc c cc}
\toprule
 & & & \multicolumn{2}{c}{Random holdout} & & \multicolumn{2}{c}{Forward-in-time} \\
\cmidrule{4-5}\cmidrule{7-8}
Comparison & & MdAPE & $\Delta$MdAPE [95\% CI] & $t_{\mathrm{DM}}$ APE / sq.\ log & & $\Delta$MdAPE [95\% CI] & $t_{\mathrm{DM}}$ APE / sq.\ log \\
\midrule
A2 Semi-log vs. & A1 Linear & 19.0 / 18.2 & +0.79 [+0.42, +1.22] & -10.7$^{***}$ / -4.2$^{***}$ &  & +2.79 [+1.78, +3.88] & 0.1 / 3.5$^{***}$ \\
A6 Splines vs. & A2 Semi-log & 17.6 / 19.0 & -1.41 [-1.83, -1.09] & -10.2$^{***}$ / -8.9$^{***}$ &  & -1.43 [-2.30, -0.77] & -7.8$^{***}$ / -7.2$^{***}$ \\
A4 Box--Cox vs. & A2 Semi-log & 18.6 / 19.0 & -0.47 [-0.59, -0.35] & 9.0$^{***}$ / -0.7 &  & -2.20 [-3.15, -1.46] & -5.3$^{***}$ / -7.0$^{***}$ \\
A3 Log-log vs. & A2 Semi-log & 18.0 / 19.0 & -1.03 [-1.45, -0.72] & -7.9$^{***}$ / -10.1$^{***}$ &  & -1.39 [-2.24, -0.74] & -7.1$^{***}$ / -6.3$^{***}$ \\
B2 Year FE vs. & B1 No time FE & 19.1 / 22.0 & -2.91 [-3.84, -2.06] & -8.1$^{***}$ / -7.4$^{***}$ &  & -5.65 [-6.51, -4.52] & -3.8$^{***}$ / -10.4$^{***}$ \\
B4 Month FE vs. & B3 Quarter FE & 19.3 / 19.2 & +0.18 [+0.01, +0.37] & 2.9$^{***}$ / 2.9$^{***}$ &  & -0.43 [-0.95, +0.05] & 0.7 / -0.9 \\
C3 Grid 5.5 km vs. & C2 Municipality FE & 18.7 / 19.2 & -0.45 [-1.07, +0.37] & -1.1 / -1.2 &  & +0.96 [+0.16, +1.81] & 2.3$^{**}$ / 1.6 \\
C4 Grid 1.1 km vs. & C2 Municipality FE & 21.0 / 19.2 & +1.81 [+1.24, +2.32] & 7.1$^{***}$ / 7.3$^{***}$ &  & +2.02 [+0.15, +3.59] & 8.1$^{***}$ / 4.8$^{***}$ \\
D2 Ridge vs. & D1 OLS & 17.7 / 19.3 & -1.66 [-2.37, -1.13] & -5.5$^{***}$ / -6.0$^{***}$ &  & -0.61 [-1.26, -0.17] & -5.6$^{***}$ / -4.7$^{***}$ \\
D4 Boosting vs. & D3 Random forest & 14.4 / 14.6 & -0.24 [-0.46, -0.05] & -4.7$^{***}$ / -6.7$^{***}$ &  & -0.13 [-0.37, +0.15] & -1.0 / -1.3 \\
D4 Boosting vs. & D5 Boosting, no coord. & 14.4 / 23.2 & -8.84 [-9.79, -8.11] & -10.6$^{***}$ / -16.1$^{***}$ &  & -4.99 [-6.50, -3.12] & -13.9$^{***}$ / -11.1$^{***}$ \\
D4 Boosting vs. & A1 Linear & 14.4 / 18.2 & -3.86 [-5.57, -2.38] & -10.4$^{***}$ / -11.9$^{***}$ &  & +0.84 [-1.19, +2.59] & -3.5$^{***}$ / -3.9$^{***}$ \\
A6 Splines vs. & A1 Linear & 17.6 / 18.2 & -0.63 [-1.13, -0.13] & -12.3$^{***}$ / -7.5$^{***}$ &  & +1.35 [+0.43, +2.28] & -6.3$^{***}$ / -6.2$^{***}$ \\
\bottomrule
\end{tabular}