How to board an airplane?

Everyone knows how to board an airplane, back to front. It’s logical. Back to front means that if someone is taking their time in seat 21C the person in 20A can still seat themselves.

Physicist Jason Steffen built a computer model to see how much faster back to front was relative to front to back. He was shocked. The difference was minimal. Hmm, Steffen scowled at his code, is there a better way?

What if instead of 30 to 1 or 1 to 30, a plane boarded everyone in row 30, then rows 1, 2, 3…. That might work right? The folks in row 30 would have time to stow and seat without holding anyone up.

That kinda works. Steffen’s code continued and compared the 30, 1, 2…29 option to the 1, 2,…30 option. The code noted the faster sequence, and switched around two more numbers. Again it kept the faster option and computed another switcheroo. The fastest boarding process turned out to be boarding every other row.

“It turns the boarding process from a serial process, where one person gets to their place, puts their luggage away, and sits down into a parallel process where you send in fifteen people, say in all the even rows, and they all put their luggage away and sit down at the same time. And then you send in the next group of people.” – Jason Steffen, August 2021

Steffen’s code was a Markov Chain Monte Carlo, a way to solve problems through computer code and exploration. But like wet bias or wait times, ideal solutions may not be the best.

One problem with Steffen’s method is when people travel in groups, especially families. Another obstacle is the culture of air travel, there’s some established norms. Further confounding the case is an airline’s incentives. Faster turns do matter, but relative to upgrades how much does saving time save the company?

Kelly and Crypto

There’s an idea, it’s a formula but really it’s an idea, in gambling called the Kelly Criterion. Broadly, it suggests to act in proportion to edge. Bet big when you have a big advantage. Card counters, like those in the book Bringing Down the House followed this idea.

While Kelly is math, like being Bayesian, it works as a general idea too. Most people never follow the formulaic ‘full Kelly’, rather they bet half or ‘quarter Kelly’ because there’s no way to truly know an edge. So, how exactly does it work as just an idea?

“I’ve had a ton of friends who thought Solana is the future, bought in at a couple of dollars, waited eight months and nothing happened and sold everything. Then, all of a sudden, boom Solana took off. The rapid climb is where a majority of the value capture occurred. You have to build a pretty serious conviction around something and have it be small enough dollars. You can’t say: this didn’t work I’m going to move into the next thing. You have to be able to say: I still have conviction here, I’m going to leave this be.” – Kevin Rose, September 2021

Rose practically uses the Kelly language! Rather than edge and bet he says conviction and small-enough-dollars.

This cost to benefit ratio approach is a nice way to frame decisions. While Kelly started in gambling and moved afield, anything about risk and reward, travel budgets for instance, works.

Most systems have lowish cadences: closer to construction than technology, and the reward portion takes time to compound. When that’s the case, it may help to think about how much conviction we have and how long the cycle may take.


This podcast hit my feed September 19, the same day my wife asked me to buy some Doge Coin. ‘Why’ I asked. I’d convinced her to dollar-cost-average into Bitcoin and Ethereum, but it took a fair bit of convincing. ‘I just want some’ she explained. shrug

Covid and breakfast cereal

cereal selfie

Me, a box of cereal from Aldi, and our kitten. When I bought this cereal the checkout process was 40% faster than rival stores. Plus the cost savings! Sure I had to collect my cart – with the quarter deposit in hand – and also return the cart, but often I meet someone half way and we do the Aldi parking lot exchange of quarter for cart and some goodwill good-to-see-yas.

This Aldi aesthetic is intentional. The cart, the product, the extra long barcodes for the extra fast cashiers are all tactics that support a strategy. I’d heard tactics are not strategy but it’s through the Aldi aisles and Marc Lipsitch’s interviews that the idea becomes as clear and legible as that bar code.

One of the lessons from Covid is how much conditions matter. We’ve learned that individual treatments are dependent on disease stage. We’ve also learned that societal actions are dependent on infection stage. The travel ban, Lipsitch said in May 2020, “was a tactic not a strategy, it was an attempt to show we were doing something rather than a piece of a strategy to make us safe from this virus.”

Strategy is important because our resources are limited. Sure, I’d love to invest in the cryptocurrency of the moment as a lottery ticket but there’s no extra dollars in our investing budget to allocate to a different strategy.

“In the beginning of the intense phase, New York City was working very very hard to do contact tracing at a time when they knew they had lots of cases and didn’t know about most of them. That’s exactly the setting where contact tracing can’t work. No matter how hard you fight the 10% you know about, you’re not doing anything about the rest.” – Marc Lipsitch, May 2020

When tactics fit together like puzzle pieces it creates a beautiful strategic picture. Aldi’s boxes are optimized for speed rather than customer acquisition. Classic cereals use bright colors and cartoons to scream pick me! The cereal aisle is the competition. It’s Cap’n Crunch vs Cinnamon Toast Crunch. Aldi’s products are private labels, so the competition is between big box stores not boxes in stores. The Aldi CAC is speedy checkouts, self-service, and quality goods.

A good strategy has a collection of homeotelic responses. Aldi is one example, but they’ve had almost eighty years to figure it out. Covid is a non-example, but we’ve learned some good lessons and it probably won’t happen again.


There’s a certain amount of what economists call ‘transaction utility’ at Aldi too, we like finding deals. Also, Lipsitch is such a balanced voice on Covid or any field with some uncertainty in the future.

Creativity through randomness

“There’s a great point in your book,” host Adi Wyner says, “where your coach tells you you’re coming in too high in the tournaments.”

“This realization happens pretty early on. It’s six months into my poker playing and I’m very happy I’ve been cashing in poker tournaments. Say you buy in for $100, but the prize money is very heavy up top. Maybe only ten people cash and the person in tenth gets $110. You make a little money on your entry fee, but first place might be $10,000. That’s the disparity. If you consistently cash, but bust out soon after it means you are losing money because it’s not just entry fees, but hotels, travel, non-cashing tournaments.” Maria Konnikova, Wharton Moneyball, June 2020

Konnikova had “settled” on a strategy that seemed okay, but was not. Her coach nudged her off it, framing the true costs of winning poker.

Sometimes a coach knows what to do. Sometimes we are just figuring things out.

“One thing that this pandemic has made us realize is a collective failure of imagination. I’ve been modeling pandemics for twenty years. I’ve been modeling for local agencies, for federal agencies, and all of our models up until 2019 pretty much assumed that our next pandemic was going to be an influenza pandemic. A lot of our planing had been around making sure we had medical counter measures for influenza, playbooks, and game plans. The assumption was that there would be a six-month timeline for vaccines and we would use non-pharmaceutical measures in the interim time period. Covid19 really took us by surprise.” – Lauren Ancel Meyers, University of Texas College of Natural Sciences, March 2021

Covid took us by surprise, in part, because we lacked a coach. In these cases we need creative solutions. Lacking that, random ones work too.

“Each evening during their hunting season, the Naskapi Indians of the Labrador peninsula determined where they would look for game on the next day’s hunt by holding a caribou shoulder bone over the fire. Examining the smoke deposits on the caribou bone, a shaman would read out, for the hunting party, the points of orientation of the next day’s search.” – David Stark, The Sense of Dissonance, August 2011

Stark makes the point that this randomization element meant the tribe would not necessarily return to the last place they succeeded. But it also wasn’t totally random. The hunters still used their very particular set of skills on the hunt.

Lots of life is a balance of “do what I know works” and “find what works next.” The specific mix is contextual, but if we find ourselves in need of a change, and lack a coach, maybe a shaman can point us in the right direction.


Thanks Thomas for the shoulder bone source. Konnikova’s book, The Biggest Bluff chronicles her journey from starter to ‘casher’. We’ve touched on this idea here too: Local maxima of bees, marketers, and NASA engineers.

A landmark numbers walk

We tend to remember more when things are connected. We tend to remember more when there is a story.

For instance, about 1,000 ants equal the length of one beetle. Rather, one Beetle, 1,000 of which lined end to end equal about the length of Central Park. Imagine that. One-thousand VW bugs lined up along the length of Central Park with one-thousand ants lined up along each bug.

Now another step, 1,000 Central Parks is about the width of Australia, ten of which is about the length of the equator.

That’s a nice story and it gives us some Landmark Numbers.

“What I mean by landmark numbers is something that sticks in your brain, you don’t set out to memorize it but it sticks in your brain as a reference point. It becomes a ready reference for you to relate to. These are numbers where, if you have them ready, they help you make yardstick comparisons of the things you hear about. It’s something where you hear a number on the news you go: ‘Hold on.That’s not a big number because it compares to this landmark number in some way.'” – Andrew Elliott, Talks at Google, December 2018

Another landmark number is 4 million. That’s about the number of Americans of any single age. That’s via Tim Harford.

Landmark numbers fit nicely with Maxims for thinking analytically. Richard Zeckhauser suggests that simple cases, extremes, and everyday analogues help us think better. A basic understanding needs context though, and landmark numbers provide just that.


Similar to Landmark Numbers is thinking like Fermi.

Tailing Aaron Rodgers (part three)

It’s time to update two of our ongoing projects. First, to revisit the idea of Aaron Rodgers throwing less than 38.5 touchdowns. The point in parts one and two were to not think specifically about what might happen but think about the states of what could happen. We reasoned there were a lot more things that would influence Rodgers to throw fewer touchdowns rather than more.

Well, no one predicted this. Rodgers now has three games (with the snowy Seahawks showing) with zero touchdowns.

Another idea to update is ‘or the field?’ Are certain events more or less predictive than others? The Wharton Moneyball hosts note that the NCAA Men’s Basketball tournament odds are out.

“We need to do our calculation, how many teams do we have to go down until the odds get to about fifty percent? You probably have to go down six or seven teams, I think I’m still taking the field. I’ll give you Gonzaga, Michigan, Kentucky, Texas, UCLA, and Duke and I’ll take everyone else.” – Eric Bradlow, Wharton Moneyball, November 2021

Well, here’s how the different sports stack up.

November field update

In the EPL and Men’s tennis the top three favorites have a larger cumulative expected odds than NCAA Football and the NBA which have larger cumulative odds than MLB, NFL, or NHL while NCAA basketball seems to be the most unpredictable. The larger the favorites, the thinking goes, the more predictable the skill and the less influential the luck.


Tom Brady continues to chug along contra to the Rodgers reasoning, needing to average 180 passing yards in his remaining games or even just 240 if he misses two. One explanation here is that positive early variance (four games over 375 yards passing) changes things a lot. Prior to this year, Brady only had 23 games with that many yards or more.

The JTBD of FIRE

Sometimes the best way to see a thing is to reframe the situation. We’ve looked at FIRE (financial independence retire early) a couple of times: the FIRE Reddit survey and homeotelic responses. But, what’s the job to be done of FIRE?

When asked what’s worth spending money on, Mr. Money Mustache suggests two further questions:

“So instead of thinking about what’s worth spending money on, I encourage people to break it down more like this: What things really make me happy in life, and which things bring me stress or unhappiness? What is the most effective and least costly way to cut out some of that stress and bring more of the happiness into my typical week?” – Pete Adeney, Outside Magazine, July 2021

What’s the job of money? One way to figure that out is answer the happiness and stress aspects of the question. And this is the job to be done for financial independence retire early – more happy less stress.

This is more tricky than it sounds. FIRE has a number, traditionally 25x expenses. We like numbers like this. Numbers like this offer comfort in their certainty. But numbers don’t answer hard questions, questions about being stressed and being happy.

In an interview with the Financial Times, Adeney is asked to coach two FIRE strivers. Should they quit their teaching careers to make more money (with more stress). Adeney flips the question around. Rather than viewing it as a money question, he frames it as an enjoyment question. Like denominating work trips in time rather than dollars, denominating work in quality rather than quantity (of dollars) shifts the question. The guests like their jobs of the moment, and that Adeney says, is part of what they’re working for anyway.

Financial goals are proxies for something else, the job to be done. And we’ve collected many ways to hire for all kinds of jobs.

Here’s the JTBD Twitter tread. Here’s a (short) JTBD book I wrote.

What to think while waiting

David Henderson recalls his first class with Armen Alchian in 1972, who started class noting that if someone understands the incentives they can understand a lot of ‘mysterious’ behavior.

“On the first day of class he said when we went to the bookstore we’d be in a long line and we’d be angry about that. But we shouldn’t be. We should be happy because it means economics works. The people working are on a standard wage and they don’t have a strong incentive. There’s no ownership, no one gets a big benefit if they do better.” – David Henderson, September 2021

We should be happy to wait? Kinda.

One theme around here is the value of curiosity. Mostly that means to wonder how and why and when things happen – or even when they don’t happen. And incentives are ripe for thought.

We’ve looked at prediction incentives, Marine incentives, and the incentives of salting roads. There’s music incentives, be careful what you count. And football recruit incentives, more careful counting.

Incentives come up so much because one way to be curious is to ask: why does that happen? and part-of-the-reason that happens are the incentives.

This kind of curiosity takes work. Like exercise takes calories, crypto (or cars) take gas, or relationships take conversations – curiosity takes work. To be curious is to think, wonder, and ask questions. To be curious is to move past the simple story and see what else is there. Sometimes there’s not more, sometimes there’s incentives, and sometimes there’s something unexpected.

One of the highlights of my interneting has been writing a post about curiousity for Ribbon Farm.

Cold War incentives

“We’re mostly pretty right,” I told my daughters (13/11). The gist was that our diet is pretty good, but some of what we do will be wrong, we just don’t know what. Even though we shifted to eat slightly less meat, thinking like Bayesians even in the kitchen, I’m 100% sure we are not 100% right.

Related is the idea of incentives. We think our current incentives are aligned, and they may be, but they too need occasional updates. Hopefully exposure and examples tune us in to them a little more.

To set the scene, it’s 1983. The Berlin wall has been up for two decades. Ronald Reagan has been president for three years and he’s rattling the Soviet Union. The U.S. is conducting war games, which is exactly the pretense the Soviets planned to use to disguise their first strike. The Soviets have an information problem. They need to orient themselves.

“They (the Soviet Union) started an operation to look out for indicators that the Americans were preparing to launch a nuclear attack. Are the military mobilizing? Were blood banks being stored up in case the casualty rate increased? Eventually it became completely absurd. Agents were told to count the lights on in the Pentagon in Washington or the Ministry of Defense in London. If there were more than a certain number, this would clearly conclude they were plotting away at night. And, if they came up with ideas they would get promotions. The agents in the field didn’t get promotions for saying nothing. You only got promotion for finding evidence that, yes, they are planning something.” – Taylor Downing, September 2021

This is the opposite of the don’t just do something principle (part of the Favorite Ideas Daily Email), which notes that sometimes the best action is not to act. But it’s hard to reward inaction that leads to a good outcome. That’s just not how we see the world.


The seeds of the ’80s were laid in the post-war alignments. A few favorite bits: Dan Carlin has a great podcast episode about the Cuban Missile Crisis (1962). Konrad Schumann jumps over (1961) the barbed wire wall, and it’s fascinating to think that this thing basically showed up overnight. There is also a documentary on YouTube about building a tunnel, maybe the first reality TV?, under the wall to save some college friends.

Roulette with Bobby

A friend wants to pay off his mortgage in the next three years. He’s got two young kids. He’s younger than me. Meanwhile, I refinanced into a new thirty year mortgage. If he pays off his home debt it will be quite an accomplishment.

Bobby’s plan is different from mine. But I don’t know that he’s wrong. Personal finance is more like cooking than baking. We looked at, for instance, a 15 or 30 year mortgage?

In a way Bobby and I are at the roulette wheel. He’s bet on black. I’ve bet on red. One of us will be right, but we can’t know ahead of time. Most of personal finance is reducing the range of choices to just good options. It feels like we’ve both done that.

The analogy of roulette also works because rather than red or black, the ball could land on green. Despite planning, we both could be wrong.

It’s also important that we have designed our systems. Sometimes we think knowledge leads to action, but around here we know that design rules the day. Bobby has a plan to pay off his mortgage early – that plan is the design. Our family has automatics contributions – that’s our design.

“If someone says financial literacy at a party I basically give them a thirty minute lecture. The idea is that in a perfect world, if someone is taught about FICO and the impact on their life, they would take actions to improve their FICO score. This is just not what researchers have found – and it’s really robust…the punchline is that environment matters.” – Kristen Berman, All the Hacks, October 2021

Roulette, as an investment, is not in the range-of-good-choices. But as an analogy it fits nice. Prepare and pick from prime possibilities but remember the ball might not bounce any of those way.


There’s a lot about design here. It’s one of my 62 favorite ideas.