Subnational Population Estimates

The "census" is the most complete and reliable source of information on the number of people in a certain country with: (1) well-developed administrative records systems (e.g., vital events registration); (2) regular census counts; and (3) no mandatory population registration systems, such as those found in most European countries. This holds for subnational areas as well - stated/provinces, counties, cities, census tracts, and even city blocks. However, a census is a time-consuming and costly endeavor and therefore only conducted every 5 to 10 years. Due to the potential for constant and sometimes quite rapid population change, especially at the subnational level, census statistics for every tenth and even every fifth year are often inadequate for many purposes. To fill this gap, population estimates are used, calculating denominators for vital rates and per capita time series, establishing survey controls, guiding administrative planning, developing marketing, and for descriptive and analytical studies.

In order or meet the need for current population figures, a number of "postcentral" estimation methods have been developed, virtually all of which can be categorized into two "traditions:" (1) demographic; and (2) statistical - sample surveys. The methods found in the "demographic tradition' are more frequently used because they are inexpensive compared to surveys. However, existing descriptions of methods in the demographic tradition are incomplete, outdated, or both and, moreover there are relationships between some of the methods found in each tradition that have been not been explored. This book fills in these gaps by providing a comprehensive and current description of methods that fit within the demographic tradition and showing the links between selected methods in both the demographic and sample survey traditions.