Category Archives: Uncategorized

Political Sunday Morning

Some links that will fill you with outrage:

Police Carelessness Wakes Local Citizen

Tuesday morning I was woken up at 5AM by a police siren. As I lay awake, I started thinking. I couldn’t be the only one woken up. Should police cars use their sirens at night? It seems like a classic example of diffuse costs and easy-to-see benefits. But is it worth it? Let’s make a quick back-of-the-envelope calculation.

The cost of running a siren at night can be modeled by the following equation (I love Fermi problems!):
LengthDriven * (2 * SirenDistance) * Density * PctWoken *
DailyIncome * ProductivityLoss

where:

  • we start with the LengthDriven with the siren on
  • multiply by twice the SirenDistance, how far away on each side of the police car a person can hear the siren, to get the geographic area affected
  • multiply by the Density to get the number of people potentially affected
  • multiply by the PctWoken to get the number of people who were woken up
  • multiply by the average DailyIncome to see how much economic value those people create each day
  • multiply by the ProductivityLoss (as a percent) that they experience when groggy to see how much economic value was lost by the siren

This model makes some assumptions. It assumes the police car drives in a straight line, that the density is uniform, that the PctWoken is constant within the SirenDistance and zero outside of it, that everyone works (so ignoring children), that everyone works a day shift, that the ProductivityLoss is independent of DailyIncome, etc. But it seems like a reasonable first step.

Let’s plug in some values:

LengthDriven = 0.25 miles

SirenDistance = 400 feet \approx 0.08 miles

Density = 18,187 people/square mile in SF (from Wikipedia)

PctWoken = 5% of people. I made this up out of nowhere.

DailyIncome = $45000 yearly per-capita income in SF / 200 work days per year = $225 per day

ProductivityLoss = 25%, I made this up too

This gives us an economic cost of $1023 every time a police officer flips a siren on at night.

Even if this only happens once per night in SF, it creates a cost of $375,000 over the course of the year — equivalent to the salary of about 4 police officers, or about 1% of the SFPD’s budget. Use of sirens also appears to be dangerous. I wonder what the benefits are — how much additional public safety is provided for this cost?

I reached out to the SFPD asking if they have any guidelines about siren use — stay tuned.

What is an order of magnitude?

I’ve always wondered exactly how to define an order of magnitude. At ideas42 I had a particular colleague with a PhD in Econ; one time I mentioned that I think use it in a “fuzzy” way, and he responded that he always uses it in an exact way.

So what is the exact way? I think there are actually two ways to use the phrase. Is it a property or is it only a relation?

  1. Property: every number has an order of magnitude that is equivalent to its power of ten (so the OOM of 153 is 2 because 153 = 1.53 * 10^2). This implies a relation: two numbers have the same order of magnitude if each of them has the same order of magnitude, and you calculate the difference in their OOMs by subtracting one from the other.
  2. Relation: two numbers x and y, with x < y, differ by N orders of magnitude if

    (x * 10^N) < y < ( x* 10^(N-1) )

Notice that these two definitions have different “predictions”! Example: is 153 an order of magnitude more than 53? Definition (1) would say yes, but Definition (2) would say no.

The Wikipedia page actually uses both definitions without trying to explain the contradiction — the first sentence is a statement of definition (1) but the John Baez quote is definition (2).

The general principle is that objective-sounding, mathematical terms get used for rhetoric even when they are loosely defined; dig deep and nothing is as precise as it seems.

How do you use the phrase?

Get Broader

Convene five of your friends who collectively have some expertise in each of the following:

  • Physics
  • Chemistry
  • Medicine
  • International Politics*
  • Literature
  • Economics

Every two months, read one book / paper by each of that year’s Nobelists.  Meet and discuss. Make the economist wear a special badge.

*For the peace prize, of course. I couldn’t figure out what it means to be an expert in peace.

Uber Gets Insightful

Uber is sharing anonymized data with Boston policymakers.

The data will provide new insights to help manage urban growth, relieve traffic congestion, expand public transportation, and reduce greenhouse gas emissions.

This is an interesting dataset for an urban planner. And Uber did well to anonymize to ZCTA instead of giving individual addresses.1 NYC made a mess of things in June 2014 when trying to do something similar.

But using Uber’s data to actually make decisions is ludicrous. Urban planning, like most policymaking, is about how to best distribute scarce resources. It is political. Look at Uber’s example uses:

Uber’s transportation policy

If Boston actually uses Uber’s data to decide which potholes to fill first, they are not going to fill many potholes in poor neighborhoods. If Boston uses Uber’s data to add additional metro stops, they will not add metro stops in poor neighborhoods.

The first questions any data analyst should ask with a new dataset are:

  1. How was this data collected?
  2. What are its blind spots?

And the blind spots here are both large and systematic. Note, however, Uber’s vacuous language above: this data will provide “insights”. They are too smart to say explicitly “this is the only data source you should use for your city planning.” But without a similarly rich dataset on the whole city, the data will only provide “insights” about how to help rich folks.

And, by the way, be wary of people peddling insights. If an insight held up to rigorous analysis, we would just call it a conclusion.

What do you think about Uber’s influence on urban policy?

  1. Though some interesting data is lost here. For example, is the rider’s destination on a busy avenue (to a store/restaurant) or a residential street (personal visit)? []

Social Justice Mural

San Francisco is full of amazing murals! Here are some details from one I particularly like, on 25th and Mission.

All you need to know about the NFL’s Personal Conduct Policy

“Discipline may be imposed in any of the following circumstances:

  • [Various criminal offenses]
  • [Some other stuff]
  • Conduct that imposes inherent danger to the safety and well being of another person”

Tell. Me. More.

Seriously, everything that’s wrong with the NFL can be found in its Personal Conduct policy. The league sees itself as the national religion, transcending common concerns of law and operating according to its own moral standards. In truth it is distinguished from a neighborhood cockfight only by its scale and hypocrisy.

Did you know? The league office is a non-profit association which in 2013 paid $0 in income tax but $45 million dollars in salary and bonus to its moronic commissioner. Individual teams also benefit enormously from publicly-funded stadiums and tax breaks. Maybe this why the conduct policy is frantically trying to preserve “public confidence in the National Football League.”

Snails

I wrote this in an email to myself on December 28, 2013. Why?

Every time someone comes to my apartment, they make fun of this one enormous painting on my wall. It’s two snails climbing a hill, done pretty clearly by a child. I found it next to a pile of trash on a beach in Tel Aviv and sat there for maybe 30 minutes using a butter knife to pry out all the staples connecting it to the wooden frame. Then I rolled it up and brought it home, all so my friends could make fun of it constantly. But something about it really speaks to me.

Edit: Josh Katz points out that I later abandoned this painting back to the trash, on Bergen Street.

Become Interesting

Do you know someone who always has interesting things to talk about? They have a secret, but it’s probably more mundane than you think. I’d bet they just subscribe to a cool email newsletter. (Classic fundamental attribution error alert!) Here are my current favorites:

wearable computers, drones, biohacking, geoengineering, rockets, digital mapping, coercive feedback loops, autonomous everything, representing the Internet in art, synthetic biology, machine logic, weapons, artificial life, the future of work, corporate surveillance

independent art, weird events, strange happenings, unique parties, and senseless culture in new york city

Any that I’ve missed?