Figure 3.3

Racial/ethnic attribution assumptions for population projections.

a particular racial/ethnic group, we call this the extremely high attribution assumption.

Neither of these assumptions is plausible. To provide more realistic bounds, we examined data on actual racial and ethnic attribution. This information underlies a medium assumption about racial/ethnic attribution rates for multiple-ancestry persons. We assume identification rates that are 20 percentage points lower and 20 percentage points higher, respectively (see Figure 3.3).

In summary, we rely on six different assumptions about the combined effects of exogamy and racial/ethnic identification to illustrate future change in the racial and ethnic composition of the U.S. population. Two extreme and unrealistic assumptions capture the possibility that either none of the multiple-ancestry persons or all of them will choose to identify a particular ethnic background as their primary affiliation. Current attribution rates form a medium assumption, in contrast with a continuation of the conventional baseline assumptions for population projections. And we vary the current attribution rates to illustrate realistic changes in low and high attribution rates (see Appendix 3.B: Table 3.B).

The United States is currently the third most populous nation in the world, after China and India. How large will the United States become in future decades? Will its rate of growth, which has slackened in recent decades, revive? And how much difference will immigration make?