Indirect methods of collecting data are required in countries and periods where full data are not available, such as is the case in much of the developing world, and most of historical demography.
Kaudset andmete kogumist kasutatakse sellistes riikides ja sellistel ajaperioodidel, mil kogu andmestik puudub, peamiselt arengumaades ja ka ajaloolise demograafia puhul.