[null,null,["最終更新日 2025-08-25 UTC。"],[],[],null,["# National-level modeling\n\nMeridian supports national-level models, although we recommend that you\nuse the geo-level model when possible. The national-level model is a special\ncase of the geo-level model with only a single geo. There is no separate model\nclass.\n\nThe following parameter restrictions apply, and are automatically enforced, when\nyou use the national-level model:\n\n- \\\\(\\\\eta\\^{\\[M\\]}_i=0\\\\) and \\\\(\\\\beta_{1,i}\\^{\\[M\\]}=\\\\beta_i\\^{\\[M\\]} \\\\ \\\\ \\\\forall i\\\\)\n- \\\\(\\\\eta\\^{\\[OM\\]}_i=0\\\\) and \\\\(\\\\beta_{1,i}\\^{\\[OM\\]}=\\\\beta_i\\^{\\[OM\\]} \\\\ \\\\ \\\\forall i\\\\)\n- \\\\(\\\\eta\\^{\\[RF\\]}_i=0 \\\\) and \\\\(\\\\beta\\^{\\[RF\\]}_{g,i}=\\\\beta\\^{\\[RF\\]}_i \\\\ \\\\ \\\\forall i\\\\)\n- \\\\(\\\\eta\\^{\\[ORF\\]}_i=0 \\\\) and \\\\(\\\\beta\\^{\\[ORF\\]}_{g,i}=\\\\beta\\^{\\[ORF\\]}_i \\\\ \\\\ \\\\forall i\\\\)\n- \\\\(\\\\xi_i\\^{\\[C\\]}=0\\\\) and \\\\(\\\\gamma_{1,i}\\^{\\[C\\]}=\\\\gamma_i\\^{\\[C\\]} \\\\ \\\\ \\\\forall c\\\\)\n- `unique_sigma_for_each_geo = False`\n\n| **Note:** Population scaling has no effect in the national-level model."]]