In genera, "self reporting" needs to be viewed as the untrustworthy statistics it is. I hear it a lot recently in the social siences. And media happily parrotting the results, as proof of whatever they are currently trying to push. I wonder how much of these self-reported issues would be seen in a completely different lens if those asked were forced to discuss their answers within a certain peer group. "What, you say you're poor, with that car and that house?"
Also consider that some of the respondents are actually "bragging" about living paycheck-to-paycheck so they don't seem any poorer than anybody else, when they are actually not even sustainable and deeply know they are heading downward toward bankruptcy or something like that unless things look up.
