Max Sawicky makes the mistake of reading only the Washington Post rather than the Nick Eberstadt paper on which the Post piece is based, and says something worse than dopey:
The fundamental value of the measure is to compare different points in time, not to provide a scientific assessment of deprivation at any point in time. Criticizing it in this dimension is idiotic. A rate of 11.7 percent means nothing in and of itself. It could mean something compared to, say, 10.5. The rate is based on a family budget that inevitably derives from prevailing social standards, not the cost of biological survival.
Had Max bothered to even read the beginning of Eberstadt's lengthy paper, he'd have known that, in fact, Mollie Orshanky, an economist at the Social Security Administration, devised it to be a fixed and unchanging measurement of absolute poverty. She based it on the cost of providing food at a minimal level (i.e. 'biological survival' as we emphasized in the hapless Max's prose).
Whether one agrees with Eberstadt's analysis of its efficacy, is irrelevant to the history of the metric.