One of the real problems is that Monthly Year-over-year numbers are very noisy. Forget for the moment the previously discussed flaws in the median versus Case-Shiller or other index.
The following will be true for any monthly index.
Problem #1. You are starting with a monthly number that varies a lot because of small sample size.
Problem #2. You are taking a difference of two different monthly numbers. Anyone who took (or more precisely remembers ) statistics can tell you that differencing two noisy estimates results in an even noisier estimate.
Example.
The monthly yeay-on-year change in 92106 (Point Loma) for July ’06 according to DQnews was -26%. However, for June ’06 this number was +7.9%.
Last month would we be asking why and trying to explain why the price in Point Loma is still increasing ???
Be careful when considering these monthly numbers to justify anything.
