Extra! Extra! Home Prices Flat!

You might have noticed the confusion of headlines today, ranging from "Home Prices Up," according to the Associated Press to "Home Prices Dip," according to Reuters.

What's going on? All of these presumably intelligent journalists are looking at the same report, S&P's Case-Shiller 20-City Home Price Index for November. You'd think they could agree on what it says.

The truth of the matter is the index has stayed about the same since August. The shift in November is so small that it can be read as either rising or falling, depending on whether you adjust for the season.