https://assets.pewresearch.org/wp-co...si2-appc-1.png
Sampling a population, how does it work?
Edit: Hey, they even had specifics per country.
Afghanistan
Sample design: Stratified area probability sample of all 34 Afghan provinces (excluding nomadic populations) proportional to population size and urban/rural population.
Mode: Face-to-face adults 18+
Languages: Baloch, Dari, Hazara, Pashto, Uzbek
Fieldwork dates: Nov. 27–Dec. 17, 2011
Representative: Nationally representative of 94% of the adult population.
Design effect: 3.4