Sampling structure used in each country
| City 1 | City 2 | |||
| Order A | Order B | Order A | Order B | |
| Male | ||||
| 18–24 years | 2 groups | 2 groups | 2 groups | 2 groups |
| 25–34 years | 2 groups | 2 groups | 2 groups | 2 groups |
| Female | ||||
| 18–24 years | 1 group | 1 group | 1 group | 1 group |
| 25–34 years | 1 group | 1 group | 1 group | 1 group |
The two cities in each country were Dhaka and Chittagong in Bangladesh, Beijing and Fuzhou in China, Cairo and Menia in Egypt, Delhi and Kolkata in India, Jakarta and Yogyakarta in Indonesia, Mexico City and Monterrey in Mexico, Manila and Pampanga in the Philippines, Moscow and Kostroma in Russia, Istanbul and Adana in Turkey, and Ho Chi Minh City and Hanoi in Vietnam.