Governments, schools and companies all keep track of your race. The stats they collect are used to track the proportion of blacks and whites who graduate from school, for example. They tell us how many people identify themselves as Native American or Asian. They help us to measure health disparities between races. But there's a problem with all of those statistics and with the deeper way that we think about race. NPR's social science correspondent Shankar Vedantam is here to explain. Hi, Shankar.