Jeff Kaufman  ::  Blog Posts  ::  RSS Feed  ::  Contact


recent posts on blogs I follow


Circumferential Lines and Express Service

In a number of large cities with both radial and circumferential urban rail service, there is a curious observation: there is express service on the radial lines, but not the circumferential ones. These cities include New York, Paris, and Berlin, and to some extent London and Seoul. Understanding why this is the case is useful […]

via Pedestrian Observations September 15, 2019

Reframing the evolutionary benefit of sex

From the perspective of an organism trying to propagate its genes, sex is like a trade: I’ll put half of your DNA in my offspring if you put half of my DNA in yours. I still pass one copy of my genes onto the next generation per unit of investment in children, so it’s a … More Reframing the evolutionary benefit of sex

via The sideways view September 14, 2019

The Case for a High Carbon Tax

Reading a bunch of people criticize green politics on the grounds that it imposes unreasonable reductions in living standards has clarified something for me. There’s extreme right criticism of Angela Merkel’s latest statement that climate protection is vital, accusing her of deindustrializing the country in the name of green-left ideology; from the left, Branko Milanovic, […]

via Pedestrian Observations September 13, 2019

Bear store

A preschool game that’s been particularly popular and versatile with my kids. Materials: Pennies Collection of counting bears or any other small objects One person is the storekeeper and sets out the bears in any way they want. The other people are customers and bring some pennies. The storekeeper sells the bears to the customers. […]

via The whole sky September 9, 2019

The Future is not Retro

One faction of urbanists that I’ve sometimes found myself clashing with is people who assume that a greener, less auto-centric future will look something like the traditional small towns of the past. Strong Towns is the best example I know of of this tendency, arguing against high-rise urban redevelopment and in favor of urbanism that […]

via Pedestrian Observations September 9, 2019

Metro-North Doesn’t Know Best Industry Practices

Governor Ned Lamont’s plan for speeding up trains between New York, New Haven, and Hartford seems to have fallen by the wayside, but Metro-North and the Connecticut Department of Transportation are still planning for future investments. Several high-level officials met with the advocates from the Connecticut Commuter Rail Council, and the results are unimpressive – […]

via Pedestrian Observations September 6, 2019

Graveyard Shift at Dawn Dance

I would say I’m alllmost recovered from the all-nighter I pulled this weekend calling the graveyard shift (4AM–7AM)—but heck, what a blast! Here’s the program I called (most of these walked through minimally or not at all): 50/50 — Bob Isaacs Fiddler’s Fling — Cary Ravitz (Will Mentor var.) Maliza’s Magical Mystery Motion — Cary Ravitz Rollin’ to the Grey Eagle — Hank Morris Read Between the Lines — Bob Isaacs The Young Adult Rose — David Kaynor Treasure of the Soda Bar — Maia McCormick Cheat Lake Twir…

via Maia Calls Dances September 4, 2019

Stuttgart 21’s Impending Capacity Problems and Timed Connections

The largest single transportation project in Germany today is a new underground main station for Stuttgart, dubbed Stuttgart 21. Built at a cost of €8.2 billion, it will soon replace Stuttgart’s surface terminal with a through-station, fed in four directions by separate tunnels. The project attracted considerable controversy at the beginning of this decade due […]

via Pedestrian Observations September 1, 2019

Some open problems in P2P routing

Imagine a world where some pairs of whom want to talk to each other—each person has a unique n-bit identity (e.g. 64-bit strings), and wants to send a message to someone with a particular identity. The number of people is ballpark exp(n), I’m imagining ~10 billion. We’ll start with a graph G, where people know how to … More Some open problems in P2P routing

via The sideways view August 25, 2019

How replaceable is public key crypto?

Suppose that there were was no number theory, no elliptic curves, no lattice-based crypto. Perhaps because our universe was rigged against cryptographers, or perhaps because our society had never decided to explore abstruse mathematics. How bad would this be? Would electronic commerce be impossible? Would modern society crumble? In this post I’ll explore the possibility that … More How replaceable is public key crypto?

via The sideways view August 24, 2019

Absolute scale corrupts absolutely

The Internet has gotten too big. Growing up, I, like many computery people of my generation, was an idealist. I believed that better, faster communication would be an unmitigated improvement to society. "World peace through better communication," I said to an older co-worker, once, as the millenium was coming to an end. "If people could just understand each others' points of view, there would be no reason for them to fight. Government propaganda will never work if citizens of two w…

via apenwarr August 19, 2019


At naptime Anna listens to recordings of novels recorded by Jeff’s grandmother. It is the main way she will know Winnie, as it is the main way I have ever known Winnie. Some of the recordings are missing parts, and Suzie often fills in the first few sentences, her cadence echoing the distinctive pattern of […]

via The whole sky August 18, 2019

One Night Ultimate Werewolf

I really like One Night Ultimate Werewolf (ONUW), and recommend trying it out. The Daybreak expansion is also good (but I’d skip the later games in the series). App For those who’ve played a lot and wish the night took 20 seconds rather than a few minutes, I’ve made an app that you can download … More One Night Ultimate Werewolf

via The sideways view August 18, 2019

Insect ethics for parents

I walk past the neighbor’s garden and feel habitual comfort at the sight of bees clustering in the Russian sage. Bees are good. Bees are pollinators. Why is that good? Because I want my apple tree to bear fruit. Is it good to be a bee? What is it like? I have no idea. I […]

via The whole sky August 6, 2019

Flat taxes are neutral under log utility

(Cross-posted from facebook.) If welfare grows with log income, then a flat 50% tax actually has no impact on my incentive to work—I get half as many dollars per hour worked, but I’m twice as poor so I value each dollar twice as much. (That is to say, the income effect exactly offsets the substitution … More Flat taxes are neutral under log utility

via The sideways view July 27, 2019

Interpersonal rules for preschoolers

(which we hope they will carry into adulthood) Consequences matter. If you were kicking your legs near your sister and you didn’t exactly mean to kick her but your foot did crash into her, you’re being reckless. You never need to give hugs or kisses if you don’t feel like it. No complaining or threatening […]

via The whole sky July 22, 2019

Nice things

Last night a friend of a friend invited us swimming at a private pond in a Boston exurb. Part of me felt suspicious of the place. Something about the feeling of “this is something rich people do” and the knowledge that the adults chatting in deck chairs were doctors and professors made me almost allergic. […]

via The whole sky July 15, 2019

Files are fraught with peril

This is a psuedo-transcript for a talk given at Deconstruct 2019. To make this accessible for people on slow connections as well as people using screen readers, the slides have been replaced by in-line text (the talk has ~120 slides; at an average of 20 kB per slide, that's 2.4 MB. If you think that's trivial, consider that half of Americans still aren't on broadband and the situation is much worse in developing countries. Let's talk about files! Most developers seem to think tha…

via Dan Luu July 12, 2019

*Why Nations Fail* and the long-termist view of global poverty

Within the effective altruism community, people often talk about “long-termist” vs “short-termist” worldviews. The official distinction between the two is that short-termists prioritize problems by how they affect people alive today, while long-termists prioritize problems by how they could affect humanity’s entire future trajectory. In practice, people usually treat …

via July 7, 2019

Instead of “I’m anxious,” try “I feel threatened”

cw: teaching to learn I have a long history with anxiety, and I’m pretty good at noticing when it’s happening. The problem is that I’m always anxious. Noticing anxiety doesn’t snap me out of anxiety– in fact, it often produces meta-anxiety, anxiety about feeling anxious. So I’ve tried a simple reframe lately, and I’m liking […]

via Holly Elmore June 20, 2019

Scrupulosity: my EAGxBoston 2019 lightning talk

This was a 5 minute talk, so I basically only had time to read the slides (dynamically!). I’m going to provide the slides and whatever extra info I said at the time in italics and give commentary and context in plain text. Obviously, this is a matter of degree. It’s not a disorder unless it’s distressing […]

via Holly Elmore May 2, 2019

Alternative beauty: my tummy pokes out

I think I'm pretty good about ignoring what I'm "supposed" to be doing with my appearance to the extent that I don't find it useful or fun. But I've been at war with my belly since it came on the scene at adolescence.

via Holly Elmore April 30, 2019

The log/event processing pipeline you can't have

Let me tell you about the still-not-defunct real-time log processing pipeline we built at my now-defunct last job. It handled logs from a large number of embedded devices that our ISP operated on behalf of residential customers. (I wrote and presented previously about some of the cool wifi diagnostics that were possible with this data set.) Lately, I've had a surprisingly large number of conversations about logs processing pipelines. I can find probably 10+ already-funded, seemingly successf…

via apenwarr April 26, 2019

Multiverse of minds

Everyone dwells in their own universe– a dream made up of sense data, culture, beliefs, historical contingencies, and idiosyncrasies. We all share an external reality (as far as we know), but none of us actually lives there. We live in our own universes in our minds. Dreams, delusion, and psychosis vividly demonstrate the extent to […]

via Holly Elmore April 23, 2019

The Turing Test podcast is back with Bryan Caplan!

Because of my illness and Ales’s graduation, the Harvard Effective Altruism student podcast, the Turing Test, had about a two year hiatus. Julia Edsparr and Jen Eason have stepped up to help me finish what I started. There are several unreleased interviews from before the pause, but one less today, because we released Episode #7 […]

via Holly Elmore April 15, 2019

Reflections on My First Techno Contra

Last weekend, I called my first techno contra (as part of a double dance at CDNY to celebrate the wedding of two of our lovely dancing humans 😍). It turns out, to no one’s surprise, that calling techno is a fair bit different from calling a regular evening dance. Here are my reflections on calling my first techno (including a bunch of great advice from folks on SharedWeight’s Callers’ Listserv). + If you can, listen to the tracks in advance! I worked with DJ Flourish (Mark Moore) from Philly—he’…

via Maia Calls Dances April 7, 2019

Programmer migration patterns

I made a little flow chart of mainstream programming languages and how programmers seem to move from one to another. There's a more common kind of chart, which shows how the languages themselves evolved. I didn't want to show the point of view of language inventors, but rather language users, and see what came out. It looks similar, but not quite the same. If you started out in language A, this shows which language(s) you most likely jumped to next. According to me. Which is not very scie…

via apenwarr March 18, 2019

Quotes from 1992

I was recently recommended to read the book Accidental Empires by Robert X. Cringely, first published in 1992 (or was it 1991?) and apparently no longer in print and also not in e-book format. To my surprise, it turns out has a solution for this, an epically user-unfriendly "virtual library card" (which is still worth it if you need to read a book) in which they apparently receive one physical copy of a book, scan it, and lend it out digitally, one person at a time, using an ag…

via apenwarr March 8, 2019

You have more than one goal, and that's fine

When people come to an effective altruism event for the first time, the conversation often turns to projects they’re pursuing or charities they donate to. They often have a sense of nervousness around this, a feeling that the harsh light of cost-effectiveness is about to be turned on everything they do. To be fair, this is a reasonable thing to be apprehensive about, because many youngish people in EA do in fact have this idea that everything in life should be governed by cost-effectiveness. I&…

via Giving Gladly February 19, 2019

Randomized trial on gender in Overwatch

A recurring discussion in Overwatch (as well as other online games) is whether or not women are treated differently from men. If you do a quick search, you can find hundreds of discussions about this, some of which have well over a thousand comments. These discussions tend to go the same way and involve the same debate every time, with the same points being made on both sides. Just for example, these three threads on reddit that spun out of a single post that have a total of 10.4k comments. On …

via Dan Luu February 19, 2019

A checklist for stock option offers

A friend of mine was looking at some job offers from startups recently and asked me for advice on how to think about the equity awards he was offered. This depends a lot on details that companies often don’t give you unless you ask. So I ended up writing …

via February 16, 2019

Forget privacy: you're terrible at targeting anyway

I don't mind letting your programs see my private data as long as I get something useful in exchange. But that's not what happens. A former co-worker told me once: "Everyone loves collecting data, but nobody loves analyzing it later." This claim is almost shocking, but people who have been involved in data collection and analysis have all seen it. It starts with a brilliant idea: we'll collect information about every click someone makes on every page in our app! And we'…

via apenwarr February 9, 2019

Why are gradual static types so great?

My theory: they’re actually the optimal point in language design space, for a few underappreciated reasons.

via February 6, 2019

The best RSS reader is Kindle4RSS

I really enjoy using RSS to get updates from my favorite writers. But recently I noticed that my RSS feed was starting to get the same distracting pull as Hacker News. I was still under the thumb of the little red badge! To escape, I decided to experiment with reading …

via January 31, 2019

Improve Your Community With This One Weird Trick!

Hey experienced contradancers! Have you been looking for a new way to contribute to your dance community? Here’s one that I’ve been trying. It’s really small, and has the potential to make a really big impact on the quality of our dances, especially as more and more of us get on board with it. Ready? Here it is: Be quiet when the caller starts talking, and don’t talk through the walkthrough. That’s it. Really. If you want to go one step further, you can be the person who gently reminds people to …

via Maia Calls Dances January 31, 2019

Words Don't Help Beginners

I’ve been contradancing for over eight years, and can jump into even the most complex and falling-apart of contras and still have some idea of what’s going on. But last summer at English-Scottish-Contra Week at Pinewoods, I tried Scottish Country Dance for the first time and I had an experience I haven’t had for quite a while: I was completely at sea in a set dance. Scottish isn’t too different from contra and English, and I got along okay when I had a walkthrough. (Not great, mind you, but I ma…

via Maia Calls Dances January 21, 2019

My 2018 donations

This year I met my donation goal again, and donated in the same proportions as last year.

via January 20, 2019

Worth keeping

(Epistemic status: quick speculation which matches my intuitions about how social things go, but which I hadn’t explicitly described before, and haven’t checked.) If your car gets damaged, should you invest more or less in it going forward? It could … Continue reading →

via Meteuphoric December 7, 2018

No one is a statistic

I’m late to the party, but I've been thinking about the documentary “The Life Equation” about how people use data to decide make life-and-death decisions. The central example is a woman named Crecencia, a mother of seven who lives in rural Guatemala and has cervical cancer. The doctor treating her knows that screening other women for cancer is more cost-effective than treating this woman, and that the community doesn’t have enough money to fully fund both. The filmmaker writes: “Crecencia’s…

via Giving Gladly October 10, 2018

Are ethical asymmetries from property rights?

These are some intuitions people often have: You are not required to save a random person, but you are definitely not allowed to kill one You are not required to create a person, but you are definitely not allowed to … Continue reading →

via Meteuphoric July 2, 2018

Personal relationships with goodness

Many people seem to find themselves in a situation something like this: Good actions seem better than bad actions. Better actions seem better than worse actions. There seem to be many very good things to do—for instance, reducing global catastrophic … Continue reading →

via Meteuphoric May 14, 2018

On Finding Purpose

We’re often taught about the importance of “finding your purpose” as you set out into the world and choose your pathway forward. The words change–sometimes it’s ‘purpose’, but you might also find your ‘bliss’, your ‘passion’, your ‘voice’, your ‘career’, or your ‘calling’–but the narrative remains the same. Whatever it is, you’ve gotta find it. And … Continue reading On Finding Purpose → The post On Finding Purpose appeared first on Hollis Easter.

via Hollis Easter April 13, 2018

Realistic thought experiments

What if… …after you died, you would be transported back and forth in time and get to be each of the other people who ever lived, one at a time, but with no recollection of your other lives? …you had … Continue reading →

via Meteuphoric April 4, 2018

The fundamental complementarity of consciousness and work

Matter can experience things. For instance, when it is a person. Matter can also do work, and thereby provide value to the matter that can experience things. For instance, when it is a machine. Or also, when it is a … Continue reading →

via Meteuphoric March 28, 2018

Fsyncgate: errors on fsync are unrecovarable

This is an archive of the original "fsyncgate" email thread. This is posted here because I wanted to have a link that would fit on a slide for a talk on file safety with a mobile-friendly non-bloated format. From:Craig Ringer <craig(at)2ndquadrant(dot)com> Subject:Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS Date:2018-03-28 02:23:46 Hi all Some time ago I ran into an issue where a user encountered data corruption after a storage error. Po…

via Dan Luu March 28, 2018

Computer latency: 1977-2017

I've had this nagging feeling that the computers I use today feel slower than the computers I used as a kid. As a rule, I don’t trust this kind of feeling because human perception has been shown to be unreliable in empirical studies, so I carried around a high-speed camera and measured the response latency of devices I’ve run into in the past few months. Here are the results: computerlatency(ms)yearclock# T apple 2e3019831 MHz3.5k ti 99/4a4019813 MHz8k custom haswell-e 165Hz5020143.5 GHz2G commo…

via Dan Luu December 24, 2017

How good are decisions?

A statement I commonly hear in tech-utopian circles is that some seeming inefficiency can’t actually be inefficient because the market is efficient and inefficiencies will quickly be eliminated. A contentious example of this is the claim that companies can’t be discriminating because the market is too competitive to tolerate discrimination. A less contentious example is that when you see a big company doing something that seems bizarrely inefficient, maybe it’s not inefficient and you just lack…

via Dan Luu November 21, 2017

XLR Mic Mute Switch with LEDs – Proof of Concept

Purpose I play music on stage, and that usually means using amplification (PA) systems. The bands I play with (Frost and Fire, The Turning Stile+, and others) typically have a bunch of musicians playing a host of instruments, each with their own microphones. Consequently, we need a lot of mic mute switches. The enemy of … Continue reading XLR Mic Mute Switch with LEDs – Proof of Concept → The post XLR Mic Mute Switch with LEDs – Proof of Concept appeared first on Hollis Easter.

via Hollis Easter September 30, 2017

How to Test Thermostat/Thermal Fuse in Kitchen Tools

How to test thermostat and thermal fuse units on kitchen appliances (espresso machine, coffee maker, rice cooker, pressure cooker) with a multimeter. The post How to Test Thermostat/Thermal Fuse in Kitchen Tools appeared first on Hollis Easter.

via Hollis Easter September 14, 2017

Use Up That Zucchini – Googoots / Cucuzza Recipe

Delicious crispy caramelized zucchini with garlic, basil, mint, red wine vinegar, and olive oil. Easily scales up to use all the zucchini in the house, and it's quick! Googootz! The post Use Up That Zucchini – Googoots / Cucuzza Recipe appeared first on Hollis Easter.

via Hollis Easter August 27, 2017

Hotline Memes

Jennifer Battle asked the National Association of Crisis Organization Directors’ mailing list for some uplifting hotline memes to use in training, since there didn’t seem to be that many available. Here are my first responses. (please feel free to use these if you like)   The post Hotline Memes appeared first on Hollis Easter.

via Hollis Easter May 24, 2017

Two standard donations and one new one

Here are three places Jeff and I are donating this year. The first two are similar to what we’ve been doing for years, and the third represents a change.Direct workJeff and I want to support work that directly makes the world a better place. (Some arguments against falling into a “meta trap” here.) As usual for us, this year we’ve given just over half our donations to direct work. We made these donations to the Against Malaria Foundation, one of GiveWell’s top picks, except for small amounts th…

via Giving Gladly December 30, 2016

Practical steps for self-care

Last week the Boston Effective Altruism group had a discussion on self-care for altruists. I've written about the topic before, but I wanted to share some of the more practical advice people had. Think beyond day-to-day choicesSelf-care isn’t just short-term decisions like whether to make time for yoga tonight. It’s larger life decisions too, like what job to take, where to live, how to budget money, and how to make time for partners, friends, and family.For me, having children was self-car…

via Giving Gladly June 15, 2016

Why I pledged

Almost four years ago, I pledged with Giving What We Can. Members pledge 10% of their incomes to the best charities they can find (with students and those with no income pledging 1% of their spending money).In the time since, I've felt good about making this commitment. I like having it as part of my routine, something that I know is part of my plan in the years to come. It's a confirmation of what I value—a safe and healthy life not just for me and mine, but for all families around the…

via Giving Gladly December 16, 2015

An Interaction or Not? Understanding a Few ML Algorithms via an Example with No Evidence Either Way

My latest blog post helps to explain a few statistical/ML models by whether they learn an interaction in a toy example Since Github Pages is way nicer than Blogger, I'm writing over there at now. To keep old posts alive, these pages at will remain as is.

via David Chudzicki's Blog March 4, 2015


I've moved here.

via David Chudzicki's Blog June 2, 2014


I was converting a PNG (which represented partials sums of the Weierstrass elliptic function) to a GIF and was confused about why the PNG looked fine at low resolution but the GIF looked bad. Then I learned that GIFs can only use 256 colors and we have to do something to map the many colors to the fewer colors. We could just use the closest available color in the new set of colors, but that results in sharp jumps and "color banding" where the colors change. So instead we use (and Image…

via David Chudzicki's Blog January 21, 2014

Interactive Lissijous Curves in d3

On a visit to San Francisco's Exploratorium, I saw an oscilloscope they had making Lissijous curves. So I decided to make a version in d3: You can play with it (and see the code) here

via David Chudzicki's Blog January 21, 2014

A Bayesian Model for a Function Increasing by Chi-Squared Jumps (in Stan)

This post will describe a way I came up with of fitting a function that's constrained to be increasing, using Stan. If you want practical help, standard statistical approaches, or expert research, this isn't the place for you (look up “isotonic regression” or “Bayesian isotonic regression” or David Dunson, whose work Andrew Gelman pointed me to). This is the place for you if you want to read about how I thought about setting up a model, implemented the model in Stan, and created graphic…

via David Chudzicki's Blog October 17, 2013

via openring