Thursday, 5 June 2008

Can someone check my maths

The May house price data is just out from the Halifax. As expected, the price decline is dramatic. The Halifax press release claims that seasonally adjusted prices are down 2.4 percent this month, while on an annual basis, prices are down 3.8 percent.

However, I found it difficult to reconcile these numbers with previous data. To see why, here are all the numbers from their press release.

All Houses, All Buyers Index (1983=100)
Index (seasonally adjusted) 595.9
Monthly Change -2.4 percent
Annual Change -3.8 percent
Standardised Average House Price (seasonally adjusted) £184,111

Last month, the average price in April was £189,027, while last May, the price was £196,720. I calculate the monthly price fall to be 2.6 percent, while the annual fall is 6.4 percent.

Perhaps, the Halifax have readjusted earlier data, more maybe I made a mistake. As I said, I can't seem to reconcile the headline numbers with the ones in the Halifax data set. Strange, don't you think. Any explanations.

According to the Halifax, prices peaked in August, when the average prices was £199,600. Since then, prices are down 7.7 percent.


Anonymous said...


Have you thought about expressing current prices by date. By this I mean "We are now back to Jun 2006 levels" or something.

What I'm trying to bring into focus is the idea of "if you bought later than this, you've been had" or a "the market has given back all profits since then".


chris said...

You're right - prices were 6.4% down year on year in May.
Halifax's 3.8% fall refers to the three months to May 2008, compared to the three months to May 2007.

Anonymous said...

Mmm - wasn't the index for April published on May 2nd? I wonder why we have had to wait until the fifth of June for this one... perhaps they were too busy with the rights issue, dealing details for which were made publi on the third... has that affected their view somehow? Brian

info said...

Halifax use a 3 month rolling average for their YOY figure (I think they only started doing this at the peak) and they revised down their original August peak figure.

Damn lies and statistics (and all that)

aSteve said...

Info, I think you're right.

I had a similar "Y'what?" moment with Nationwide - who, I believe, do the same thing. It makes all their data lag more than necessary - however, because the raw data is available, you can use your own workings.

Both Halifax and Nationwide understate both rapid rises and declines in prices.

Mark Wadsworth said...

What info says.

Nick's idea is a good one. You could set up a series of posts called "Rolling back the years"!