Social scientists have shown that situational factors, such as perceived benefits or disadvantages associated with a choice of racial identity in a particular situation affect an individual's response to a question on racial identity. A further consideration is that some of those who chose not to mark more than one race on the 2000 census may identify themselves as multiracial in another situation-on health surveys or college application forms, for example. Another factor that makes racial classification difficult is that many people are not aware of their own genealogy or ancestry. For example, people who marked more than one race in the 2000 census represent only a subset of the total population of multiracial people because some may be unaware of their family backgrounds, and some who are aware may decide to report just a single race. Finally, the method used in collecting racial data also influences racial reporting.
People respond differently to mail surveys versus personal interviews, for example.
Thus, it is unrealistic to expect a high degree of consistency across different data sets because an individual's answers may vary over time and across different situations.