Differential population growth leads to changes over time in group percentages of country population. Disadvantaged minorities, for example, typically have higher birth rates than others. We did not attempt to correct for this factor, other than to rely on the most recent census and expert estimates available. In our judgment it is a relatively small source of error, or indeterminacy, by comparison with others described above. Net Changes in MAR Population Estimates Many MAR estimates of group population for 1995 were revised as a result of the process described here and all 1998 estimates are derived from and consistent with the corrected 1995 proportions.
More substantial changes are few, affecting less than a tenth of the groups.
Some are due to decisions to re-define the group. For example all Brazilians with some African ancestry are now counted as Afro-Brazilians rather than those of purely African descent. Other substantive changes are due to identification of better sources, especially more reliable expert estimates and more recent census data. The aggregate impact of all changes is small, however.