One role the blogosphere might be able to play is in the rapid transmission of ideas across disciplines. In theory generalists could emerge who scan the styized facts as they appear on blogs and compline them into a more robust theory.

Jim Hamilton has an excellent post on price that consumers actually pay. Using supermarket data its shows that although discounts are rare a huge fraction of items are sold at discount.

I found Figure 3 below particularly interesting. The red, short-dashed line is the regular, non-sale price for Peter Pan that one would infer from Figure 1 above. The blue, long-dashed line is the regular price for Jif from Figure 2, and the green, short-dashed line is the regular price for a third brand. The solid black line is the average price consumers actually paid for peanut butter. Its dynamic behavior looks nothing like any of the three regular prices.


I remember reading some papers about this in graduate school. At the time we were thinking about willingness-to-pay and consumer surplus.

However, its interesting to see how the fraction of items sold at a discount moves with a recession, and whether prices are really more pro-cyclical than we think.

Just thinking about this suggests  to me that a few very sticky prices – ones that I like to think of as obligations – like mortgage contracts might account for a lot of macroeconomic fluctuation.

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