Paternoster was known for his research on racial disparities in the application of capital punishment in the United States. This research includes a study of racial bias in Maryland's death penalty, commissioned by the state's then-governor, Parris N. Glendening. Paternoster then spent 2 and a half years analyzing data before releasing the study in 2003. The study reported that black defendants who killed whites were much more likely to be sentenced to death than defendants who killed blacks, whether the defendants were black or white. In a 2006 dissent, Maryland Court of AppealsChief Judge Robert M. Bell cited Paternoster's research on this topic as evidence that capital punishment in Maryland was biased against blacks. In his dissent in a case brought by death row inmate Vernon Evans, Jr., Bell wrote, "The Paternoster study provides substantial evidence that the Baltimore County State's Attorney's Office singled out black defendants from similarly situated white defendants when choosing against whom to seek the death penalty."