The Racial Tipping Point – Freakonomics – Opinion – New York Times Blog
The study (published in The Yale Law Journal) found — after controlling for a host of other variables — two independent racial effects:
1. African-American cab drivers, on average, were tipped approximately one-third less than white cab drivers.
2. African-American and Hispanic passengers tipped approximately one-half the amount white passengers tipped.
African-American passengers also seemed to participate in the racial discrimination against African-American drivers. While African-American passengers generally tipped less, on average they also tipped black drivers approximately one-third less than they tipped white drivers.