U.S. was modeled with a number of sowe.conomic characteristics, among which are female labor force participation rates, male and female incomes, percent rural, percent Mormon, percent Hispanic, and net migration rates. Although regression equations with these variables were found to capture most of the variation in White fertility rates, this approach was termed 'virtually useless' for projecting fertility, because forecasting changes in these variables proved more difficult than projecting fertility itself (Isserman 1986). So far, such macroeconomic models have been most useful to project future migration rates (American Statistical Association 1977).

# ANALYSIS OF FERTILITY TRENDS

A description and analysis of fertility trends in various countries will be provided to serve as the basis for a revised approach to projecting fertility. The first step in analyzing trends is to distinguish different stages io fertility transition and to classify countries by stage. The second step is to provide a representation of trends within each stage. Then we consider the question of when countries move from one stage to another.

The fertility data used are World Bank estimates for the period 1955-85, derived from a number of sources, such as the U.N. _World Population Projections, 1988 Revision,_ national statistical offices (mainly for developed countries), fertility surveys, and the Demographic and Health Surveys. Many of the TFR estimates from the U.N. are obtained through backward projection, and are therefore influenced by estimates of mortality and age structure. To complement the examination of these data, survey or census-based estimates are used exclusively in some- parallel analyses.

## **_Stages In fertility_** _transition_

Current total fertility rates around the world range from around 8 (Rwanda, Yemen Arab Republic) to around 1.4 (Federal Republic of Germany, Italy, Luxembourg). Depending on the TFR level and its recent trend, countries can be categorized into three grolvns. Countries or economies with high fertility in whic a fertility has not yet declined in a significant way (to be -rined below) are said to be pretransitional; those in which fertility is currently declining in a significar. y are said to be transitional; and those in which fertility has reached low levels (near or below replacement) are said to be posttransitional. A fundamental tenet of demographic trans;tion theory, which defines these stages, is that all countries sooner or later move from the pre-transitional stage through the transitional stage to the posttransitional stage; once countries have made the transition, they remain at relatively low levels of fertility.

The first versions of demographic transition theory (Notestein 1945; Davis 1963) did not make explicit how a demographic transition is identified. Not every fertility decline can be called transitional: pre-transitional countries often experience small changes in TFR, but declines are usually not sustained; they remain therefore pre-transitional. Thus, it is necessary to specify what type or quantity of fertility decline is transitional. In this paper, we use a decline of at least .5 points in TFR over a quinquennium as identifying the start of fertility transition. Additionally, we assume that any country with a TFR below 4.5 has begun the transition (Bulatao and Elwan 1984:62-66). Table 1 classifies countries by fertility stage using this definition.

Pre-transitional countries. These differ widely in their level of fertility, with TFRs ranging from 8 to 5. There is little intentional control of fertility through contraceptive use; fertility differentials are the result of different marriage pattems, different durations of breastfeeding and postpirtum abstinence, and the level of sterility. Pre-transitional fertility trends are sometimes downward, sometimes upward. Figure la shows fertility levels and trends in a number of typical pre-transitional countries. These data have been smoothed by backward projection but nevertheless illustrate the variability among pretransitional countries. Some of the upward trends are believed to result from declining sterility and reduced breastfeeding.

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