Why property markets resist comparison

The obvious question about a network of property datasets is which country is more expensive. It is a harder question than it looks, and the honest answer today is that IndexProp does not publish one. Here is precisely what stands in the way, because the obstacles are more useful than a number that ignores them.

1. The populations are different products

Singapore’s national figure is public housing: HDB flats, sold on 99-year leases under eligibility rules, in a market where public housing is where most of Singapore’s residents live. The United Kingdom’s is the whole private market, freehold and leasehold, houses and flats. Setting one against the other compares a public-housing resale market with an entire private one.

2. Floor area is not one measurement

A per-square-metre price is a ratio, and its denominator is defined differently in each market: an Energy Performance Certificate’s measured area in one, the housing authority’s own recorded area in the other. Two figures built on two definitions are not made comparable by sharing a unit.

3. Currency conversion adds a third moving part

Converting one market’s prices into the other’s currency introduces an exchange rate with its own date, its own volatility and its own choice of spot-versus- average. A converted gap can move on a day when no home changed hands in either country, which is a poor property of a property statistic.

4. The mix adjustments are not the same operation

Both markets correct for the fact that what sells is not a random sample of what exists. They do it differently: one weights property types by their share of past sales, the other weights flat types by the national housing stock. Both are defensible. They are not interchangeable, and a headline that ranked one against the other would be ranking two estimators as much as two markets.

5. Some questions have no data at all

Two questions get asked more than any others: where rental yields are highest, and where housing is least affordable against local incomes. Neither can be answered from these two datasets. The UK market publishes no rent figures, deliberately: the available national rent series is a mean, and dividing a mean rent by a median price produces a number with no clean interpretation. Singapore publishes gross yields but no income data at this geography, and says so on its own methodology page.

What would change this

A third market, or a rent register on the UK side, or an income series at a matching geography in Singapore. When one of those lands, this piece will say what it made comparable and what it did not. Until then, each market answers the questions its own data supports.