Wednesday, August 21, 2013

Marginal


Perceptions of Toxic Exposure: Considering “White Male” and “Black Female” Effects 

Nnenia Campbell, Christine Bevc & Steven Picou 
Sociological Spectrum, July/August 2013, Pages 313-328 

Abstract: Research on risk perception suggests that social position produces identifiable patterns in the way that people evaluate potential risks, particularly in locally polluted environments. The present study builds upon this literature by examining perceived risk of exposure to environmental toxins among residents located on the Gulf Coasts of Louisiana and Mississippi following Hurricane Katrina. Demographic information from a sample of residents was used to explore the concepts of the “white male effect” and the “black female effect,” discussed in recent research. In support of existing literature, we find that white males tend to be exceptionally risk accepting when asked about potential toxic exposure, whereas black females tend to be exceptionally risk averse compared to other groups. Our analysis suggests that awareness of differential vulnerability and long-standing conflicts over environmental contamination across the Gulf Coast region have left some residents with heightened sensitivity to the possibility of a locally polluted environment. 

Nod to Kevin Lewis

I always wonder about the confounding effects of average and marginal perceptions.  To the extent that white men are wealthier than black women, on average, they are likely to live in different neighborhoods and have different environments.  White men are much less likely to suffer daily exposure to toxic chemicals.  Thus, AT THE MARGIN, they are more tolerant.  But they would have to suffer a lot of exposure just to get to the point where black women start.

Now, that may not be true in this case, and the study may be fine.  But in general if you find  a difference in averages you should think about whether it comes from a difference in margins.