**LU It4NTC"ON**

# APPENDIX: DATA AND<sup>METHODS</sup>

# Nature and Sources of Data

The key data for these projections are<sup>base-year (mid- 1985) total population estimates and</sup> age-ex structures, base-period (1985-90)<sup>mortality, fertility, and migration rates, and assumed trends</sup> in the rate. The sources of these<sup>data will be described, as well as the sources for similar data going</sup> beck to 1975 and for recent trend<sup>data on other indicators. A country-by-country listings of the</sup> sources of **base** data is in Table Al.

## _Popuiaon_ **_and Age-Sex Structure_**

Estimates of the total mid-year population<sup>in 1980 and 1985 are obtained from the most</sup> roeent reliable sources. As far as<sup>possible these are recent census totals projected to the desired</sup> year, with appropriate adjustments for<sup>under-reporting. A number of such estimates made by the</sup> United Nations (U.N.) Population Division<sup>(in the forthcoming</sup><sup>_World Population Prospects 1990)_</sup> have been adopted. For countries<sup>with dated or unreliable census data, other official estimates may</sup> be taken, often from the U.N. _Population_<sup>_and Vital Statistics Report_and occasionally from</sup> Sovernment publications. Other<sup>sources of estimates include Eurostat (1989) and the U.S. Bureau</sup> of the Cenwus (1985; Jamison, Johnson, and<sup>Engels 1987). The specific source of information for</sup> each country is listed in Table Al.

The mid-1985 population of each<sup>country is distributed by age and sex using a</sup> percentage distribution obtained<sup>from one of a few sources. One source is</sup><sup>_World Population_</sup> _Prospects 1988,_ which has distributions<sup>calculated by the U.N. Population Division from census data</sup> adjusted for age misreporting or estimated<sup>using stable population analysis. Other sources include,</sup> for most Sub-Saharan and a few<sup>other countries, World Bank or official estimates of curmnt age-sex</sup> distribution, frequently derived by<sup>stable population analysis. The age and sex distribution for 1980</sup> is based mainly on _World Population Prospects_<sup>_1988._</sup>

## **_Mortlty Data_**

Base-period mortality levels in<sup>the projections are represented by life expectancies at birth</sup> by sex and infant mortality rates<sup>for both sexes combined. Life expectancies for the quinquennia</sup> 1975-80, 1980-85 and 1985-90<sup>were obtained from a variety of sources. A preliminary version of</sup> _World Population Prosnects 1990_<sup>was a common source. Other figures are based on official or other</sup> estimates appearing ini _Population_<sup>_and Vital Statistics Report_orgovernment publications. A few</sup> figures are taken from the U.S. Bureau<sup>of the Census (1985; Jamison, Johnson, and Engels 1987),</sup> Eurostat (1989), and Monnier (1988).<sup>These sources often report mortality levels for periods other</sup> than the desired quinquennium, or<sup>give indices other than life expectancies, or both. Some estimation</sup> and projection is then necessary<sup>to obtain the right index. In some cases, a mortality estimate is first</sup> made for an earlier period, and<sup>an estimate for 1985-90 obtained by applying the projection</sup> methodology described below.<sup>Some Bank sources are also cited in Table Al: Bank sector reports;</sup> Bank assessments, involving unpublished<sup>analysis of census or survey data; and Bank estimates, or</sup> informed judgments for which no<sup>further source can be cited.</sup> Infant mortality rates, like life<sup>expectancies, were commonly taken from the preliminary</sup> version of _World Population_<sup>_Prospects 1990._However, a number are drr,wn from</sup><sup>_Population and_</sup> _Vital Statistics Report,_ and others<sup>are estimated from diverse data. In particular, several estimates</sup> are derived frcn recent Demographic<sup>and Health Surveys. Tke mortality risk for children under age</sup> S for the current period is derived<sup>from a model described below. For earlier periods, this indicator</sup>