When IRBs are applying the federal regulatory criteria for approval to protocols involving socially or economically disadvantaged persons:

Each criterion should be analyzed in relation to the special characteristics of the populations

Explanation:

They need to do this to ensure that the people who actually approved to the protocols are not faking their economic conditions for personal benefits (such as getting accepted for government welfare program or getting a tax cuts).

The IRB need to clearly defined each characteristics that can make a person to be "disadvantaged" and demanded proof for every single persons that put in The data. (could be done by things such as submitting your salary form or copies of bank account)