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Wednesday, September 6 2006

The Privacy Continuum

The Facebook just released a new feature that shows all the recent changes from your friends on your main page. Less than a day later, there are multiple groups protesting this as an invasion of privacy; the largest I've found is nearly 25,000 students strong. This is a very important reaction that we should pay attention to: a great many people feel their privacy has been invaded, but no new information has been revealed! The new feature only aggregates publicly available information. How could that be an invasion of privacy?

Because our previous conception of privacy, as public/private, is a flawed dichotomy that must be discarded in the face of changing technology. Data is not merely private or public, known or not known. Data has an associated cost of retrieval which is either high or low. The strength of this reaction to the new feature might have caught its creators by surprise, but it shouldn't have. After all, The Facebook's walled-garden approach to schools is largely responsible for its popularity, and that approach is entirely based around increasing the cost of accessing data. No one really believes that information they enter there is private, just that it will be relatively difficult for outsiders to find. A huge amount of information had been entrusted to The Facebook with the understanding that it would be available only to other users of The Facebook, and to them only so long as they paid the time cost of looking for it. Now that time cost has been reduced to nearly zero, privacy has been reduced correspondingly. The protesting students' instinctive reaction is precisely correct; the privacy bargain has been unilaterally modified.

This is same kind of invasion of privacy being proposed by the Bush Administration in the Total Information Awareness project. No private information would go into the database, and yet aggregating that data into one place is still an invasion of privacy. We all agree that our whereabouts are not secret when we enter public spaces, yet I doubt many of us would be comfortable with the government recording our every movement. That our purchasing histories are public is no big deal when accessing one takes effort and time; they are still mostly private because most people will not spend the time to find them.

Data aggregation is an invasion of privacy because it reduces the cost of access to that data, and cost of access is the continuum upon which "public" and "private" are poles.

  • Update: 4 hours later, it's up to 85,000 students.
  • Update: A day later, it's up to 280,000 students.
  • Update: A few days later, it maxed out around 750,000 students.

Thursday, August 31 2006

Things I Didn't Know About The History Of Schools

  • In 1930, there were 260,000 schools in the USA (including approximately 150,000 ones with only a single teacher). In 2000, there were less than 95,000 schools almost none with only a single teacher. The average number of students per school size grew from 89 to 502.
  • The number of support staff per student has increased three-fold since 1950, from 1/83 to 1/27.
  • The number of teachers per student has increased two-fold since 1950, from 1/26 to 1/12.
  • The average number of years of experience for a teacher has increased 7 years since 1966, from 8 to 15. The average age of a teacher has also increased by 7 years over the same time period, from 37 to 44.

The statistics are from School Figures, which is published by the Hoover Institute. I hadn't heard of them before, but from reading their choice of statistics it's clear they're in the privatization/school-choice crowd. The idea of school choice had an appeal for me at one point, when I still believed that what made a school good could be measured by tests. School choice advocates are entirely right that if you place enough emphasis on competing for students via test scores and the school ratings based on them, you'll see scores go up. The problem with that approach is that any kind of test scores are basically broken as a measure of the success of schools.

For the first part, it's difficult to say whether test scores are truly rising or falling at all. There are a huge number of confounding factors involving demographic trends and changes in the tests themselves. Secondly, even assuming we could correctly tease out the true change in test scores, there's very little evidence that rising test scores mean better educated students. It's difficult to deny that students who score 1600 on the SATs are much more likely to be well educated and thoughtful than those who score 900. But as those 1600 point scoring students would tell you, corelation is not causation! It might be that on average tall students score higher on their SATs, but that doesn't mean giving students stilts will improve test scores.

This is all a roundabout way of saying that I don't think much of the book, although it has a lot of pretty graphs. They've managed to pull together a very large and impressive number of statistics, a few of which are meaningful and most of which are not. Other offenses include, but are not limited to: extrapolating trends from as few as two data points, representing public opinion polls as meaningful measures of something more than people's opinions, and failing to consider alternate explanations for trends. I shouldn't pick on them too much, since all of these are common crimes, but I wish for a book on the history and facts of education that I could actually recommend at some point.

Terse, to say the least

I've been thinking and talking a lot about programming language design recently. I find when discussing the relative merits of languages, I often get hung up on the question of what is and isn't possible in a decent way in any given language. So I've decided to compile a set of the ways to solve a particular problem in several different languages. Hopefully this is the first of a series.

Problem: define a function "adder" of one variable (x) which returns another function of one variable (y) that sums x + y

My answers for every programming language I've thought about or used recently, in order of decreasing length:

Javascript:

function adder(x){ return function(y){ return x + y; } }

Scheme:

(define adder (lambda (x) (lambda (y) (+ x y))))

Ruby (a Proc is not exactly like a function because Ruby is dirty):

def adder(x) Proc.new {|y| x + y }; end

Erlang:

adder(X) -> fun(Y) -> X + Y end.

Forth:

: adder quote [+ ] append ;

Arc:

(def adder (x) [+ _ x ])

Haskell (currying is cheating):

adder = (+)

C and Java got skipped because the question isn't really meaningful for them, since they don't have anonymous functions.

Tuesday, August 29 2006

Yogurt: The Unknown Danger

I recently took a plane flight. On the first segment, the TSA confiscated my shaving cream. On the second, my toothpaste. Is the government fighting a war on hygiene? If my toothpaste is so dangerous, why did you let me take it on the first flight? This seems to imply the TSA is either enforcing useless rules without purpose, or failing to enforce useful rules, or both. The loud speaker barks out more orders as I sit in the airport. The warning level is currently orange and I should be alert! Vague, passive fear - my favorite kind. Boarding with yogurt purchased from airport shops is Strictly Forbidden!

I am in shock. For once, I am in complete agreement with the TSA. Yogurt is dangerous and needs to be kept off of our planes at all costs. But I am disturbed by a glaring weakness in the system: we are still selling the very tools required to secret yogurt onto our planes.

While surely the extremely thorough security check given by the flight attendants as you board would catch a simple ruse like hiding the yogurt by placing it in a bag, I am worried they will miss other more devious possibilities. For example, they sell good, honest, plane-legal muffins in the airport. But I happen to know they do not check your muffin when you board, and it would be only too easy for a criminal to hollow out the muffin and fill it with yogurt. I expect the TSA to follow up on this glaring security hole. Muffin inspection kits should be present at every gate.

Worse yet, you could easily smuggle yogurt in your mouth. Does anyone demand to look in your mouth before you board yet? If they don't, it's critical they start. I don't believe they sell plastic bags suitable for secreting yogurt elsewhere on your person yet, but you could bring them in in your luggage. Either we need to remove all plastic bags from luggage in the security checkpoint, or we need cavity searches at the plane door. Realistically, given that the TSA missed my toothpaste so easily, we probably need both.

Sunday, August 27 2006

The Kiko Asset Sale: Finished

The auction was a success! I can't reveal the identity of the buyer quite yet, but it's a very respectable organization that I think will be a great home for Kiko Calendar. I think this venture has proven that auctioning off intellectual property assets is a legitimate revenue route for a company to take. Hopefully others will follow us in this, because so many valuable pieces of software wind up simply abandoned instead.

Tuesday, August 22 2006

The $100k Plan

Teachers are paid like mid-level administrators and given a job for skilled professionals. They raise our children every weekday. For other equivalently important jobs, we offer high salaries to attract the most qualified. Salaries are important both for the money and for the status that comes along with it.

It is difficult to recruit the best to a difficult job with low pay and status. In many places we simply can't find enough qualified teachers, let alone enough good ones. The solution to this problem is obvious, and has been proposed by many other than myself: pay our teachers more. So let's imagine a new kind of school where teachers were paid as professionals on par with doctors, lawyers, or engineers.

Starting salary at these new schools will be $100,000, compared to a current national average of $30,719. Public schools spent an average of $8,287 per child in 2004. That means each teacher must teach about 12 students to cover their salary. It's a general rule of thumb that overhead (work space, shared support staff, basic supplies, benefits) is at least 1/3 of salary; let's say it's 1/2, giving 18 students/teacher. Allowing for pay raises similar to the current system (teacher salaries reach an average of $46,597) brings that number to 27. We will ruthlessly cut anything else from our budget, because there simply won't be sufficient funds. A much lower teacher/student ratio requires structural changes to the way schools are organized.

The main consequence of this lower teacher/student ratio is a large reduction in the number of class hours available per week to each student. It simply won't be possible to fill schedules with 6 classes every day of the week. Instead, the school would therefore have to be structured much more like a college than a traditional high school. Students would take fewer classes concurrently, and classes would commonly meet only 2-3 times per week instead of every day. It also means more serious work required out of class, both by the students and the teachers responsible for them.

The low ratio also requires us to keep the schools as small as possible, so that natural social effects can help control disciplinary problems. Smaller schools require fewer support staff and less specialized equipment as well, which is good because we're not going to have a lot of extra money.

The smaller number of teachers means that each teacher is much more individually important. All other highly paid professionals have an apprenticeship style training program, and teachers would benefit from the same. Luckily, the smaller number of teachers also means that we don't have to hire as many new teachers per year, which should make it easier to provide quality training.

An incomplete list of other consequences which require thought:

  • Small schools have limited facilities and social opportunities by nature, so perhaps a coalition would be required
  • Vouchers? Charter schools? Reform of current public schools?
  • What does the distribution of teachers of subjects look like?
  • Who decides when and with what staff to create one of these schools? How is money allocated?

(Thanks to Steve for the conversation that sparked this idea and feedback)

Monday, August 21 2006

The Kiko Asset Sale

Seconded

First Post

A new blog; almost certain to be abandoned again.

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