From the author of these graphs:
The monthly sales data for Subdistrict 5E (Cole Valley/Parnassus/Ashbury Heights) is so low that running percentage declines off of median values, as I did for Noe Valley, would have been worthless. As several of your readers and I myself pointed out, it’s hard to draw conclusions when there are very few data points.
Instead I ran the percentage declines off the “95th Percentile” value, which the statisticians among your readers will know means that 95% of the sales fall below that value. Hence, it represents a “high”, while excluding the potentially aberrational top 5% of values.
After looking at this chart, I sort of threw up my hands. With only 179 sales in over 6 years, it’s not sensible in my view to draw conclusions about monthly trends in Cole Valley, let alone to compare them to Noe Valley, where the “core” area alone — Subdistrict 5C (Noe Valley) — had over 900 sales during the same period.
So I re-ran the numbers and calculated medians based on annual sales. The second chart shows the results. I think this is much easier to understand. Again, with so few sales, one should be careful about drawing any conclusions, and with only 5 sales in 2009 so far, I think it’s too early to conclude that the apparent drop in median prices for 2009 will continue to be accurate. Rather, I’d say that Cole Valley seems to have been holding up pretty well.
And we’d have to agree and argue this is yet another reason why Cole Valley is superior to Noe Valley…
Thanks again to Misha Weidman for the charts and analysis. Good to have a data geek on staff. ;-)