Declining Median Incomes?

Much is being made of figures indicating that median American household incomes have been declining in recent years.

KBJ points out that immigration could bring about such a decline, without making anyone worse off.

Let's also keep in mind that these supposed median income declines are based on household incomes. Every time a working couple divorces or separates, and one household becomes two, the median household income will drop.

When a college grad manages to land an entry-level job good enough to enable him to move out of his parent's house, the number of households increases, and the median household income (most likely) decreases.

It's possible that individual incomes in the lower income brackets have risen to a level such that a greater share of poor people can maintain their own residences, rather than living in cramped conditions with extended families. Is that a bad thing?

All sorts of factors bear on household demographics. No wonder, then, that hardly anyone who posts this map owns up to what it actually represents.