Table 2.

Selection models, stage 1

Variable	Probability of a response	Robust standards error	95% confidence interval
Log of GDP per capita	0.0822 (1.61)	0.0516707	− 0.0190972, 0.1834481
Developed	0.0137 (0.08)	0.169712	− 0.3189542, 0.3463045
Western Pacific	− 0.958 *** (− 6.26)	0.1524606	− 1.257184, − 0.659549
Asia	0.498 *** (2.27)	0.2024287	0.1013962, 0.8949019
Eastern Mediterranean	− 0.744 *** (− 4.31)	0.1764809	− 1.089974, − 0.3981816
High mortality	− 0.651*** (− 4.65)	0.1381482	− 0.9214802, − 0.3799491
Constant	− 0.271 (− 0.86)	0.319379	− 0.897074, 0.3548685
Observations	760

t statistics in parentheses

* p < 0:05, ** p < 0:01, *** p < 0:001