in stimulating economic growth; (2) the implications of developing-country urbanization*not only its pace, but also the socioeconomic composition of urban natural increase and rural-urban migration*for economic growth.

Fertility Decline and Investments in Human Capital As it is used by economists, the phrase "quality-quality tradeoff" refers to reductions in fertility levels accompanied by increases in human capital investment. Such tradeoffs are generated when families, facing new macroeconomic environments and new policies, adapt by changing their demographic behavior. When aggregated, the fertility reductions tend to slow the rate of labor force growth; human capital investment will increase capital per worker. In this way, changing demographic behavior at the family level can have an important influence on the rate of economic development.

This session will explore the connections between lower fertility and human capital investment, both at the level of families and at the level of economies. Of particular interest are factors, such as reductions in infant and child mortality, that would seem to encourage lower fertility and favor investments in human capital.

The Implications of Urbanization for Economic Growth The developing world is becoming increasingly urbanized, and over the next two decades, urban population growth is expected to well outstrip rural growth. What are the implications of this profound demographic change for economic growth prospects? This session will explore a range of issues, with particular emphasis on three issues: (1) the roles of migration and natural increase in shaping the composition of the urban labor force and its rate of growth; (2) the roles of economies of urban agglomeration in stimulating technological change; and (3) the demands that urban growth is expected to place on "natural capital," that is, on the local environmental resources of urban areas and their hinterlands.