Radar Perene / Archive / science

Housing liquidity has an index: what the ILI measures and what it does not promise

◦ Index methodology v2.2 (working papers with DOI). See the methodology.

Science

Whoever sells a liquid stock discovers the price in seconds. Whoever sells an apartment discovers the price at the end of a negotiation that can last a year — and discovers, along the way, that the "market value" in the listing was a hypothesis. Real estate is the largest store of household wealth in Brazil and, at the same time, one of its most opaque markets: no trading floor, no continuous quote, each transaction hiding particular conditions no portal captures. In that environment, the question "how much is it worth?" gets plenty of attention. The question "how fast does this turn into money?" is almost never measured.

The Housing Liquidity Index (ILI) is the house's instrument for that second question: measuring the state of liquidity in the Brazilian real estate market — the ease with which properties convert into money — as a disciplined series, not as a broker's impression. The instrument's concept, sources and, above all, limits are declared in a public working paper with a permanent DOI: The Brazilian Housing Liquidity Index, currently at version 2.0.

Measuring where there is no trading floor

The central difficulty of such an index precedes the statistics: the object does not cooperate. A market without continuous quotes forces the instrument to read liquidity through indirect signals — the traces that ease or difficulty of selling leave in the available data. This imposes a structural honesty: each indirect signal carries its own noise, its own lag and partial coverage. An index presenting itself as an exact reading of an opaque market would be lying in its very title.

That is why the ILI's editorial design inverts the indicator market's custom: the limits are not in a footnote — they share the stage with the concept. The paper declares what the measure reaches and where it sees poorly, in the same typography. In a historically opaque market, the map of the instrument's blind spots is part of the instrument.

What "does not promise" means, item by item

The ILI does not promise to state the right price of any property — liquidity and price are different questions, and confusing the two is the most common error in the real estate debate. It does not promise to predict the market's turning point: it describes the present condition of liquidity, and condition is not trajectory. It does not promise fine resolution — the specific city, the neighborhood, the property type: the reading is of the market's general state, and zooming beyond the data's resolution would produce facade precision. And it does not promise immunity from revision: the instrument is young, the object is hard, and the house's ruler applies to it as to all the others.

That last clause is not defensive rhetoric — it has a documented track record. The current version of the paper openly revises findings from earlier versions that did not hold up under re-examination; the revision is recorded in the public text itself, with the versions preserved in the repository. What that revision says about the house's method deserves more than a mention — it is the subject of the next article in this trail.

Why such an index has a DOI

The transparency contract is the same as for the whole series: concept public and immutable per version, mechanics reserved, reading exposed. But in the ILI's case the permanent record has an additional role, one that liquid-market indices need less: in a market without public prices, the definition of what is measured is the only verifiable anchor. There is no third-party quote against which to check the index — there is the conceptual contract, and nothing else. An editable document would be, here, especially cheap to corrupt. The deposit with a DOI, along the lines Track 1 describes in what Zenodo is, freezes the definition beyond the reach of the house itself — which is exactly where such a definition should live.

What the reader takes away

For those following the real estate market, the ILI offers what the sector rarely has: a series of the state of liquidity with a frozen definition, declared limits and a visible revision history. For those reading this trail for the method, the index is the collection's limit case: the instrument that measures the hardest object and, for that reason, the one that most depends on saying out loud what it does not know. The rule it illustrates applies to any indicator, from any provider: the more opaque the object, the more declared limits are worth — and the more suspicion the index that does not declare them deserves.

Frequently asked questions

Does the ILI say whether it is a good time to transact property?

No — and not out of modesty, by definition. The index describes the state of the market's liquidity; each reader's wealth decision involves variables no index contains. A descriptive instrument informs; it does not advise.

Don't liquidity and price move together?

They are related, but they are not the same measure — and the episodes in which they diverge tend to be precisely the most informative: markets where listings hold price while liquidity dries up tell a story the price alone conceals.

What is the index's geographic resolution?

The public reading is of the general state of the Brazilian market. Finer cuts run into the data's coverage — and the paper prefers declaring that frontier to feigning resolution the data does not have.

What changed between the paper's versions?

Version 2.0 openly revises earlier findings that did not survive re-examination, with the old versions preserved in the repository. The case is told in detail in the next article of the trail — as an example of protocol, not of exception.

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Continue the trail: Two versions, one revision: the ILI finding that did not survive →

House reading: today's reading is in the Diário; the episodes where liquidity was a character, in the Atlas.

Applying the ILI reading to a specific city or property type is a conversation the house has case by case.