Our purchases are sharply divided by family net wealth. It would be nice to see separate indexes for typical purchases by the top 10%, the next 40% and the bottom 50% (or perhaps five or more indexes of equal purchasing volume by net wealth).

Aggregating the prices for all consumers as if we live on the same block is a very rough measure that continues to skew the picture by overstating dollar volume and understating individual economic decisions at the extremes. The 40% of the population with negative net wealth just don't shop the same way as people with real money.

Of course such attention to detail is only necessary when the little people make a difference - apparently not in monetary policy.