あまり不景気とか地価の話は取り上げるつもりはないが、面白かったもの：

Econbrowser: Factors in local house price declines

こちらの研究から。グラフは見ての通り2000年からの上げ幅とピーク時からの下げ幅をプロットしたもの。

But by far the most important variable was the magnitude of the previous price run-up, which all by itself can account for more than half of the observed variance in the size of the price decline across different communities.

The more prices were artificially bid up, the more spectacularly they declined.

これで分散の半分以上を説明できるそうで。