Austin Contrarian

I've been promoted to "economist."

Thanks.

Graduation rates

According to a new study of graduation rates in large cities, only 58.2% of Austin's high school students earn a diploma.

AISD reassures us the real number is over 77% -- the study "doesn't adjust for things like students moving into private schools, students moving out of state and students entering home-schooling. The data our state prepares are much more precise because they are actually tracking a student over time."

I dunno.  Just eyeballing AISD's own enrollment data (pdf), the study seems plausible:

 

12th grade classes have only 80% or so of the enrollment of the 10th grade classes two years before.  And that's enrolled 12th graders.  I imagine well under 90% of enrolled seniors graduate each year.   

The pertinent question anyway is how many 9th graders graduate.  9th grade attrition is probably much higher than 10th grade because weaker students are retained in the 9th grade (note the persistent bulge in 9th grade enrollment). 

I'd be surprised if much more than half of the students who start the 9th grade end up graduating from AISD.

This is a small sample, of course; perhaps these figures are just anomalies.  And, yes, this is a crude, seat-of-the-pants analysis.  But if 77% of all high school students graduate, you'd expect that to be reflected in relative class sizes.

As for AISD's explanation for the drop in class sizes:  Sure, some of these students move away.  But some students also move into town.  I suspect that families who move to the suburbs for the schools tend to do so before their kids hit the 10th or 11th grade.  I also have trouble believing that there is a large exodus from public to private school in the middle high school years (although I'm sure it happens). 

This study blames low graduation rates -- and the alleged under-reporting of graduation rates -- on high-stakes testing.  I realize that graduation rates are ideologically fraught statistics.  But the theory makes sense to me:  High-stakes testing (and No Child Left Behind) incentivizes principals and administrators to demonstrate yearly academic improvement.  Since they (and probably teachers, too) have little real control over student improvement, their natural incentive is to run off the bad students and jigger the graduation rates to disguise what's really going on.

(Of course, this incentive exists for all schools, not just AISD, and I know that the state has elaborate rules for reporting drop outs -- I'm not accusing anyone of fraud, perhaps just creative accounting.)

Perhaps AISD should consider incentivizing those who can actually make a difference.  I don't have a problem with paying students to study -- we subsidize college education; why not high school?  There are large, positive spillover effects from education, which means people typically underinvest in their own education.  This is a classic market failure that can be fixed (perhaps) by the government setting the proper incentives.

The kind of letter lawyers would rather not receive from a federal judge . . .

   

(Not my case, thankfully.)

Small footprint indeed . . .

A fellow in Gonzalez is making 200-square foot houses.  He's using salvaged lumber and touting them as "vintage."

(H/t Newmark's Door)

PS:  The story is from a Seattle paper.

Random story of the day

Determined to out-San Francisco San Francisco, Seattle's Landmarks Board has declared a boarded-up Denny's a landmark.  The property owner was understandably "chagrined," seeing how it had paid $12 million for the lot with the intention of selling to a condo developer.   

The debate before the Landmarks Board:  Was the restaurant's architecture authentically "Googie" (no affiliation with Google)?

Its soaring, parabolic roofline is evocative of the "Googie" architectural style that started in Southern California and dominated in the 1960s, an era of American optimism amid the Cold War race to conquer space, said Alan Michelson, head of the University of Washington's architecture library and a preservation supporter.

The Googie style got its name from a Sunset Strip coffee shop designed in 1949 that featured upswept roofs, large plate-glass windows and boomerang shapes and starbursts.

Judith Sobol, a preservation consultant hired by [the owner's] team, and architect Larry Johnson said the Ballard Manning's structure was not a quintessential Googie-style building, citing a smorgasbord of various styles, including Polynesian, Scandinavian and Googie elements.

Johnson drew chuckles when he referred to the building's style as "Scandigooginesian."

Preservation-board members were divided over whether the building was truly Googie and decided to avoid basing a landmark designation on its architectural style.

"I think the building is whimsical, not Googie," said board member Molly Tremaine, who voted against the landmark designation. "It doesn't say 'I'm an architectural wonder.'

Googie architecture?

Not convinced the building was sufficiently Googie, the Board instead decided the building should be saved because it is "an easily identifiable visual feature of its neighborhood" and contributes to the neighborhood's identity.

Not surprisingly, the Board's chairman lives near the would-be condo development. 

Bayes' theorem and "Deal or No Deal"

Warning:  Off-topic.  This is an update of this post on "Deal or No Deal."  Math and other non-zoning-related stuff below the jump.   

CAFE math

From Marginal Revolution:

Via Andrew Sullivan, Eric dePlace notes that "You save more fuel switching from a 15 to 18 mpg car than switching from a 50 to 100 mpg car." And so you do. A 15 MPG car would require 1,000 gallons of gas to drive 15,000 miles while an 18MPG car could get it done in just 833 gallons. That saves 167 gallons of gasoline. By contrast, since a 50 MPG only uses 300 gallons to go 15,000 miles, upgrading to 100 MPG can't save that much gas -- the super-efficient car uses 150 gallons.

It's called "diminishing returns."  It's easy to see if you chart the number of gallons saved by improving a given gas mileage by 1 mpg, which I've done below (per 1,000 miles driven).

 

Improving gas mileage from 10 mpg to 11 mpg saves 9 gallons of gas per 1,000 miles (all else equal), while improving gas mileage from 50 mpg to 51 mpg saves just 0.4 gallons per 1,000 miles -- or just 4 gallons per year, if you drive 10,000 miles per year.

I think CAFE is a dumb piece of legislation for a bunch of reasons.  One is its focus on "fleet averages."  CAFE orders car makers to improve the average fleet gas mileage.  A car maker can do that by improving the fuel efficiency of its clunky SUVs.*  Or it can do that by improving the fuel efficiency of its already-efficient compacts.  (It can do both, of course.)  Increasing a 35 mpg vehicle's gas mileage by 10 mpg saves just 10% as much fuel as increasing a 15 mpg vehicle's gas mileage by 10 mpg.  These are perfectly equivalent methods of compliance under CAFE, though, so a car maker will choose whichever option (or combination of improvements) will cost it the least.

If you think this kind of legislation is a good thing, there's a simple fix:  mandate reduction in average "gallons per mile."  That would give a 1 mpg increase in a low-gas-mileage vehicle a lot more weight than a 1 mpg increase in a hybrid's gas mileage.  E.g., improving gas mileage from 15 mpg to 20 mpg is a 25% reduction in "gallons per mile," but improving gas mileage from 40 mpg to 45 mpg is just an 11% reduction in gallons per mile.  The car maker would have an incentive to make the improvements where they would make the most difference.

*Under the new CAFE standards, car makers will have to lump their SUVs with their passenger cars in calculating fleet averages.

Netiquette bleg

There's a blog I really like with great content on a subject that interests me.  The author, though, crams each post with irrelevant images.  I suppose he means to enliven his posts.  Instead, the images just distract from the content.  Badly.  (This isn't an Austin blogger or anyone who regularly comments on this blog.)

Can I say something? 

The picture of irony

The crape myrtle in front of my house:

My blog's reading level

M1EK writes about the same stuff, so out of curiosity I checked his blog:

I guess we're serving different market niches.