Table 3.

Response rates across various study populations.

Study populations	Mean response rate difference	P-value Wilcoxon rank-sum test
Professional role
Attendings	−1.5%	0.78
Residents	−0.5%	0.69
Medical students	+3.5%	0.54
Region
Africa	−2.3%	0.52
America	−18.5%	<0.001**
Europe	+2.1%	0.88
Eastern Mediterranean	−13.6%	0.01*
South East Asia	−15.1%	0.003*
Western Pacific	−15.8%	0.003*

^*P < 0.01,

^**P < 0.001.