jg is right. The OFHEO index is more reliable, since it tracks sales and refis of the same SFR over time, and goes back to 1976. I have NAR data that far back, and SFR and OFHEO move together perfectly. I expect the 12/01/06 OFHEO release of Q3 06, to be down significantly. New home sales median jumps all over the place, and that is the reason the median jumps around so much. Dataquick calculates the median as the weighted median of new homes/condos, resale condo, resale SFR.
The median does not track the price change of each home, but shows the mix of homes sold that month. I would be shocked if the value of a particular home fluctuated over time. Home prices move steadily up, or down, but the median can be all over the map, depending on the types of homes sold that month.
So if the median is up 5%, that does not mean your home is worth 5% more that month. Each home is still falling in value, and it will continue to do so, as long as months supply is above 8.