Table 1.

Cross-validation results for out of sample prediction of CCs across all world regions

Predicted CCOverall ρ2
Polity population0.84
Polity territory0.76
Capital population0.71
Levels of hierarchy0.60
Information system0.59
Monetary system0.53
  • Prediction accuracy is measured with prediction ρ2 (SI Appendix, Table S2). Overall ρ2 values are calculated as an average of the ρ2 values weighted by the number of polities from which they are drawn.