Posts filed under “Mathematics”

US Homeowner Vacancy Rate is 2.7%, Not 11%

I don’t know what to make of this bizarre headline from Diana Olick, who made the claim that “Nearly 11 Percent of US Houses Empty.”


Source:  CNBC


That 11% number is about 4X of what is should be, according to the data wizards at Census, and Economagic, who note that the rate was 2.7% in Q4.  (Maybe someone added 4 of these up to make a full year!)

Census Bureau‘s last news release was:

“National vacancy rates in the fourth quarter 2010 were 9.4% for rental housing and 2.7% for homeowner housing, the Department of Commerce’s Census Bureau announced. The rental vacancy rate of 9.4% was 1.3% lower than the rate recorded in the fourth quarter 2009 and 0.9% lower than last quarter. The homeowner vacancy rate of 2.7% percent was approximately the same as the fourth quarter 2009 rate, and 0.2 percentage points higher than the rate last quarter (2.5 percent).”

Here is the Economagic chart showing the US Homeowner Vacancy Rate :

Source: Economagic


I cannot figure out how she got to 11% from 9.4% apartment vacancy and 2.7% home vacancy.

If you want to play with the data yourselves, here is a Census Department spreadsheet: Table 1a. Quarterly Rental Vacancy Rates, Homeowner Vacancy Rates, Gross Vacancy Rates, and Homeownership Rates for Old and New Construction.


UPDATE February 1, 2011, 3:39pm

The best explanation I have seen is that the 11% number is technically correct, but irrelevant. It is not the Vacancy Rate, but simply the total number of structures that are unoccupied. One reader wrote:

Table 3. 14.2 million houses vacant year-round divided by 130.2 million housing units = 10.9%.

The harder question is why that’s the number she’d report. Who cares how many old abandoned farm houses there are?

The answer is that the 11% is a sensationalistic number, one that is meaningless to those following housing.

UPDATE 2 February 1, 2011, 7:39pm

The readers who sent this question in may have been confused by the Page header, which reads:  “Home Ownership Nearly 11% of US Houses Vacant

I could see how that might be confusing as to Home Ownership Vacancy Rates to some readers.



Are Defaults Really Driving Retail Spending? (April 16th, 2010)

Category: Data Analysis, Mathematics, Real Estate

Is China Really Funding the US Debt?

I keep hearing people erroneously claim that China is funding US deficit spending. It seems that every eejit with a fundamental misunderstanding of mathematics (and access to Xtranormal‘s animated talking bears) has been pushing this concept. It turns out to be only partially true — and by partially, I mean 7.5% true. But that means…Read More

Category: Credit, Mathematics, Really, really bad calls

Population 7 Billion

Population 7 Billion” is a 7-part National Geographic series on global population.

With the worldwide population expected to exceed seven billion in 2011, National Geographic magazine offers a 7-part series examining specific challenges and solutions to the issues we face. The magazine introduces the series with its January cover story “7 Billion,” offering a broad overview of demographic trends that got us to today and will impact us all tomorrow. The first in-depth story will appear in the March issue, focusing on humans’ impact on the planet’s geology. Other stories will follow throughout 2011.

See photos from 7 Billion:

Category: Mathematics, Video

Mathematical Doodling

Fantastic mathematical doodling:

Site is here:

Hat tip NY Mag

Category: Mathematics, Video

Estimates of Wealth Distribution Are Widely Wrong

I’ve been meaning to get to this chart for some time, so I am glad Good reminded me to: The actual United States wealth distribution plotted against the estimated and ideal distributions across all respondents. The actual United States wealth distribution plotted against the estimated and ideal distributions of respondents of different income levels, political…Read More

Category: Current Affairs, Mathematics, Psychology

Asymmetrical Motivation & The .299 Hitter

There is a fun mathematical discussion in the NYT Sports section today worth looking at. It turns out that major league hitters on the verge of a 3 handle batting average — .300 — hit an astounding .463 on their last at bat of the season: “Two economists at the Wharton School of the University…Read More

Category: Mathematics, Sports

Thaler on Tax Cuts

University of Chicago Behavioral Economist Richard Thaler drops some hard analysis on the tax-cut-at-any-price crowd in his NYT column this week: “Want to give affluent households a present worth $700 billion over the next decade? In a period of high unemployment and fiscal austerity, this idea may seem laughable. Amazingly, though, it is getting traction…Read More

Category: Mathematics, Taxes and Policy

Conditional Risk (or, trouble when you misapply stats)


Category: Mathematics, Weekend

Who Gets What If Tax Cuts Are Extended

The NYTimes graphic department has your Sunday morning chart porn regarding the extension of tax cuts. Its an illustration fueled by data from the Tax Policy Center, a nonpartisan research organization. The graphic shows how much Americans have gotten so far broken down by income groups. And it calculates that extending all of the Bush…Read More

Category: Mathematics, Politics, Taxes and Policy

Whatever Happened to that Apple iPhone Recall?

“If the current betting trends are to be believed, it now seems certain that a recall is in the cards” -Paddy Power, Irelands Biggest Bookmaker July 14, 2010 press release > Speaking of dumb bets: Its time to revisit a recent prediction market “winner,” and review the strengths and weaknesses of these markets: Recall this…Read More

Category: Mathematics, Really, really bad calls, UnScience