Deriving Low-Income EJ Population

Good Evening,

I have a GIS project as part of my spatial analysis subject at the University of Houston. I am undertaking an Environmental Justice (EJ) Analysis of the proposed Dallas-Houston High Speed Rail. In December 2017, the Federal Railroad Administration (FRA) published the DEIS that includes EJ analysis that uses ACS 2014 5-year estimate. I am re-analyzing the EJ analysis using the ACS 2016 5-year estimate.

I am trying to figure out how the low-income population at the block group level is determined using the ACS 2014 5-year estimate. I looked at the income tables including Table B19001 (which is households), but couldn't quite follow how to obtain the proportion of individuals as outlined in the below DEIS EJ analysis methodology: 

Low-income communities
o The combined proportion of individuals at or below the USCB’s poverty threshold living in a Study Area census block group equals 50 percent or greater, or
o The combined proportion of individuals at or below the USCB’s poverty threshold living in a Study Area Census block group equals twice (or greater) the proportion of low-income individuals in the county

For the purpose of this analysis, low-income block groups are identified where the average median income falls below $24,300 (poverty threshold for a family of four as determined by the USCB).  

Here is a sample of table showing low-income EJ by block group.

I would greatly appreciate your kind assistance.

Sincerely,

Virginia Sapkota

  • According to your notes, the DEIS EJ methodology is using poverty data to define Low-Income communities (the definitions are provided in your bullet points above). Then you say "For the purpose of this analysis, low-income block groups are identified where the average median income falls below $24,300 (poverty threshold for a family of four as determined by the USCB)." You are describing two different methods of defining low-income communities. If the point is to utilize the DEIS EJ method (for the purpose of comparison to the 2014 5-year data), then you should stick with using the poverty status tables as your source (S1701 for example). The median household income tables cannot tell you how many people are in poverty. Just because a particular block group has a median hh income lower than your selected poverty threshold does not mean that all people (or even half of the people) in that block group are in poverty. You can learn more about the poverty statistic here: www.census.gov/.../poverty-measures.html
  • In reply to Shawn Kimberly:

    Thank you very much Shawn for kindly responding! Your detailed explanation confirmed my initial confusion of the DEIS EJ methodology. After more digging, I was able to figure out that the study used poverty status tables (B17021).

    Virginia