We are in a presidential general election where debates are followed up by focus groups and massive polling to determine the "results" of a given debate....

In addition, massive and I do mean massive, polling is occurring nationwide regularly (see Real Clear Politics or Five Thirty Eight for detail).... 

These efforts are scientifically developed and complex (and not always right) but they do weigh the sample population in a balanced manner....politics uses these techniques,,,marketing is a major player...just about everybody who wants data uses these techniques....

NCR has selected 7 folks several times to get the Catholic (in this case millennial) opinion....I don't believe they have used scientific selection processes....if they have...I wish they'd mention it.....