Family budgets have been reshaped since the 1960s, and the shift is bad for most households — the big costs now are the ones hardest to avoid.

• Housing has gone from cheap to the single biggest expense for most families.
• Food, once the largest cost, is now one of the smallest.
• Health care, child care, and insurance have ballooned, with child care now eating a full salary for many.
• Student debt and higher taxes pile on top, squeezing what's left.
• The official poverty line is outdated and does not reflect these costs.

Outlook: Fixing the poverty measure would mark millions more people as poor and force more government spending, so the formula is likely to stay as it is.