Wednesday, February 14, 2007

DataQuick Revises Figures Back to 1988

From the OCRegister:

Most noteworthy in this month's DataQuick report is the fact that the market tracker has revamped its home-sales math....The changes include a broader definition of a home sale and a new way to calculate the median price. Figures back to 1988 were revamped.
From DQNews:
The change, the first since DataQuick began publishing statistics in 1989, takes advantage of significant data enhancements the past 18 years.

These changes...will take effect starting with our published January 2007 sales statistics.

Sales counts: Changes in our methodology to determine the number of sales transactions have resulted in a roughly 10 percent increase, on average, in our historical monthly sales totals. In most cases this has little if any impact on the year-over-year increase or decline in sales.

Median sale prices: The main change here is a switch from a so-called weighted median price to a straight median for our "all homes" category, which combines resale houses, resale condos and all new homes. On average, this change results in a roughly 1 percent difference in the all-home median sale price historically.

In addition, some of our other medians (for resale houses and new homes) have changed slightly because of various database enhancements. Again, these changes are mostly minor and do not alter historical trends.

1 comment:

bearmaster said...

I saw that too. I wasn't sure what a "weighted" median was but according to this page, it looks like in many cases it can turn out to just be an average:

Calculating the weighted median of a recordset

And here I've been thinking all along that they've been providing a straight median!

They say this shouldn't be a major impact but ... we'll see...