S&P CoreLogic Case-Shiller Home Price Index

The S&P CoreLogic Case-Shiller Home Price Index measures how US house prices are changing. Its clever trick is "repeat sales": it compares the price of the same house each time it sells, so a wave of mansion sales cannot distort the picture. There is a national index plus city versions; "NSA" means the figures are not seasonally adjusted.

It runs with a roughly two-month lag, so it tells you where prices were rather than where they are. Still, housing wealth affects how confident and willing to spend Americans feel, which feeds into the bigger economic story.