In drawing conclusions from Scorecard's data about environmental justice issues, each user must address three questions:
- What is the "right" measurement?
There is no convenient unitary measurement of impact. Does it depend on amounts of toxic chemicals emitted from nearby industrial facilities? On risks of particular diseases? On other factors?
There is also no single target group to measure impacts on, to the exclusion of other groups. Should impacts be evaluated on families below a particular income level? On people of one specific racial or ethnic origin, or another? On people of a certain education level, or job classification, or lack of other assets?
Scorecard shows the comparative statistics for each of four environmental burdens, on each of seven different subpopulations - a total of 28 separate comparisons for each geographic area covered. Each user of the data must decide, for herself or himself, which comparison or combination of comparisons is most significant.
- Is a numerical difference the same thing as a significant difference?
Each user of the data must decide, for himself or herself, whether a particular numerical difference is significant or not in terms of environmental justice analysis. See discussion of numerical differences.
- Are the data sufficient?
The limits of the data must be kept in mind in using any one comparison, or combination of comparisons, to draw conclusions about disparities in impact of actual environmental conditions.