John D. Cook @JohnDCook Twitter profile | Pikagi

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John D. Cook

@JohnDCook

52,622

Followers

209

Following

1,305

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35,226

Statuses

I turn business problems into math problems then solve them.

Houston

https://t.co/7yVkfwaGwl

Joined November 2008

Don't wanna be here? Send us removal request.

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@JohnDCook

John D. Cook

9 months

“What kind of math does your consulting involve?” “Sometimes fancy stuff, but often high school level math.” “Why would anyone hire a professional mathematician to do high school math?” “Because a professional mathematician can wield high school math like a professional.”

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@JohnDCook

John D. Cook

2 years

Pop songs don’t have key changes anymore.

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John D. Cook

2 months

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John D. Cook

2 months

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@JohnDCook

John D. Cook

2 years

An AI chatbot is an echo chamber, repeating the data it was trained on. If you trained ChatGPT on all the text you could find before 1880, and asked it what causes malaria, it would tell you bad air.

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@JohnDCook

John D. Cook

3 years

Calcium, magnesium, and iron in cabbage, lettuce, tomatoes, and spinach dropped 80–90% between 1914 and 2018.

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John D. Cook

4 years

“You should turn that blog post into a journal article.” Translation: You should put in 20x the effort so you can reach 1000x fewer people.

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@JohnDCook

John D. Cook

9 years

Photos of Pluto in 1930, 1996, and 2015 http://t.co/Nfw63iQBjG

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@JohnDCook

John D. Cook

6 years

First they ignore you. Then they laugh at you. Then you realize there are good reasons why your naive ideas weren’t immediately embraced, that the world is more complex than you thought.

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@JohnDCook

John D. Cook

3 years

“When you mix politics with science, you get politics.” — John Barry

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John D. Cook

3 months

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@JohnDCook

John D. Cook

6 years

Technological Stockholm Syndrome: Becoming attached to a bad technology because you worked so hard to learn it.

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@JohnDCook

John D. Cook

1 year

Why not both? At 25 I was married & studying exactly the things in the title of the book in the image.

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1 year

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John D. Cook

5 months

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@JohnDCook

John D. Cook

2 years

Robust versus Optimal

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@JohnDCook

John D. Cook

2 years

Starting to think maybe the wars I read about in history classes were a tad more complicated that they were portrayed.

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@JohnDCook

John D. Cook

5 years

One thing I learned from playing music is that audience enjoyment isn't closely related to technical difficulty. Another is that audiences prefer simple things done well to difficult things done poorly.

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@JohnDCook

John D. Cook

2 years

If a book is part of a “banned books” display in a large chain book store, it’s not really banned.

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John D. Cook

4 years

The more effective preventative measures are, the more people will believe they were unnecessary.

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@JohnDCook

John D. Cook

4 months

Grad students when they switch from watching lectures to doing research

@AMAZlNGNATURE

Nature is Amazing ☘️

4 months

Birds are fed by their parents in their infancy. When the time comes to feed themselves, there can be some confusion when the food does not go into their mouth by itself.

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@JohnDCook

John D. Cook

4 years

Fundamental idea from information theory: information is proportional to degree of surprise. The more strongly you expected an answer, the less information it conveyed.

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John D. Cook

4 years

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John D. Cook

1 year

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John D. Cook

1 year

That schadenfreude-like feeling when you realize something you felt you should learn but didn’t is now obsolete .

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John D. Cook

4 months

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John D. Cook

9 years

Productivity tip: Work hard.

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John D. Cook

8 months

Freshman: I don't know how to solve this problem. It's too hard! Tutor: OK, first let's do this tiny step. Freshman: Yeah, yeah. I know /that/. But that doesn't solve my problem. Tutor: OK, now let's take the next tiny step. ...

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@JohnDCook

John D. Cook

5 years

Hippocrates: First, do no harm. Crowd: Duh! Hippocrates: You fail to appreciate how easy it is to do harm when you intend to do good. This is not a "duh."

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John D. Cook

6 years

“I prefer butter to margarine because I trust cows more than chemists.” -- Wendell Berry

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John D. Cook

6 years

Much of my career has been to go back and actually understand what I thought I understood as a student.

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John D. Cook

2 years

"What do you see yourself doing in 10 years?" "Something that doesn't have a name yet, but that will build on things I understand now."

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@JohnDCook

John D. Cook

4 years

I RT’d AOC because she said something that made sense, that it was absurd to expect Congress to vote on a 5,000 page bill that they had only two hours to read. She then voted for the bill and deleted her tweet.

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John D. Cook

3 months

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John D. Cook

2 years

The boy who said that the emperor has no clothes may have been on the autism spectrum.

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John D. Cook

1 year

Everywhere is approximately South America

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John D. Cook

4 years

Fragility increases rapidly as you squeeze out the last bit of efficiency.

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John D. Cook

5 years

"It is entirely possible to build something without understanding it." -- George Dyson

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John D. Cook

5 years

"The best way to secure data is never to collect it in the first place. Data that is collected is likely to leak." -- Cory Doctorow

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John D. Cook

29 days

“I see you have a complex problem: it has a real part and an imaginary part.” — Richard Hamming

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John D. Cook

9 months

“Did it really take years of experience to solve this equation?!” “No, it took years of experience to write down the appropriate equation.”

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@JohnDCook

John D. Cook

6 years

Contact info:

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John D. Cook

7 months

"Not everything is Pareto distributed, but 80% of it is."

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John D. Cook

3 years

"Every person who has mastered a profession is a skeptic concerning it." -- George Bernard Shaw

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John D. Cook

7 years

I have given up newspapers in exchange for Tacitus & Thucydides, for Newton & Euclid, & I find myself much the happier. -- Thomas Jefferson

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John D. Cook

4 months

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John D. Cook

8 years

Age distribution of wall punchers

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@JohnDCook

John D. Cook

8 years

"Now I am become Data, the destroyer of theories."

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John D. Cook

2 years

“More effort is wasted doing things that don’t matter than is wasted doing things inefficiently. And if that is the case, elimination is a more useful skill than optimization.” —James Clear

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John D. Cook

3 years

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John D. Cook

5 years

Your computer doesn’t belong to you the same way a computer did a few years ago. Unless you go to significant effort to remove it, there’s a lot on your machine that’s not in your best interests.

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John D. Cook

7 years

People pay you according to how valuable they find your work, not how hard you find it. Basic fact of life many don't understand.

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John D. Cook

4 years

Looking at data can be comforting. Every time I read something alarming in the news, then look at the actual data, I feel better. News is intrinsically biased toward the exceptional. #manbitesdog

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John D. Cook

2 months

AI generated health advice.

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John D. Cook

2 years

Imagine an experiment to reverse a person’s perception of the world. It would feed the subject images in inverse proportion to their true frequency, often commonly showing rare things and rarely showing common things.

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John D. Cook

4 years

A placebo is something that works in practice but not in theory.

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John D. Cook

3 years

Just stumbled on this.

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John D. Cook

16 days

When most people say “exponential” they mean “really fast.” But that’s not what exponential growth means at all. Many things really do grow exponentially (for a while), but not everything that is “really fast” is exponential. If you earn a million dollars a day, your wealth

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John D. Cook

2 years

Engineers: Designing a saw blade is really complicated. We’d like to optimize over 100 factors but we’ll reduce it to 5 because that’s all we can handle. Politicians: Human society is simple and every problem is one-dimensional.

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John D. Cook

3 years

A PhD does not make you an expert in a field; it makes you a researcher. The goal of a PhD program is to make a beeline to some point on the frontier, not to survey the territory.

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John D. Cook

3 years

In mathematics, when you reach a point of absurdity, you stop. You either back up, because you’ve made a mistake, or you declare victory, because you wanted to show something is impossible. Bureaucracy isn’t like that. You shrug it off and keep going.

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John D. Cook

2 years

The developer caused the crash by walking in front of a video camera. The video software buffer overflowed because the flannel image was less compressible than the image of a solid colored shirt.

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John D. Cook

5 years

There's a theory that intellectual decline with age has been exaggerated because older people are less willing to play the games psychologists set for them, that psychologists confuse compliance and intelligence.

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John D. Cook

9 years

2016 = The number of ways to place two pawns on a chessboard.

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John D. Cook

2 years

My favorite debugging story concerns software that crashed only on days when the developer wore a flannel shirt.

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John D. Cook

1 year

If what you're about to say is predictable, then it carries zero information as measured by Shannon entropy. Information = Surprise. Zero surprise => zero information.

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John D. Cook

12 years

"In general you [become successful] not by knowing what the experts know but by learning what they think is beneath them." -- George Gilder

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John D. Cook

6 years

"Eroom’s law — that’s Moore’s law backward — observes that the number of new drugs approved per billion dollars spent on R&D has halved every nine years since 1950."

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John D. Cook

4 years

The best part of being an applied mathematician is that you get to "play in everyone's backyard" as John Tukey put it. I've had the opportunity to work in areas I never expected: video games, human fertility, nutrition, drones, medical devices, ... It's been great fun.

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John D. Cook

1 year

Unicode character U+1D54F "MATHEMATICAL DOUBLE-STRUCK CAPITAL X"

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John D. Cook

6 years

"I like to find (a) simple solutions (b) to overlooked problems (c) that actually need to be solved, and (d) deliver them as informally as possible, (e) starting with a very crude version 1, then (f) iterating rapidly." Paul Graham

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John D. Cook

5 years

That's interesting. Firefox is now warning you when you visit a site that has had a data breach.

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John D. Cook

2 years

No couple has ever been ready to have children. They had children anyway and figured it out.

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John D. Cook

5 years

Over-simplification comes from not seeing trade-offs. Over-complication comes from not accepting trade-offs.

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John D. Cook

3 years

Flying on an airplane greatly increases your chances of dying on an airplane. That doesn't mean flying lowers your life expectancy. It might increase your life expectancy, depending on what you do instead of flying. Risks need to be evaluated in context.

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John D. Cook

10 years

Four stages of life: 1. You believe in Santa Claus 2. You don't believe in Santa Claus 3. You are Santa Claus 4. You look like Santa Claus

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John D. Cook

2 months

If you sue a phone spammer, you’re likely to win. And you’ll get put on a “known litigants” list, the ultimate do-not-call list.

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Episode 169 — Privacy, Artificial Intelligence, and the Sales...

How do organizations convert leads into revenue? How can they do this effectively while being privacy-conscious, not bombarding people with unwanted cold calls or messages? In Episode 169, the Data...

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John D. Cook

5 years

Learned a couple useful German words lately: Amtssprache: bureaucratic clichés used to deny responsibility Verschlimmbessern: making something worse in an attempt to improve it

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John D. Cook

7 years

If Twitter keeps doubling the maximum message length every 11 years, you’ll be able to tweet War and Peace in 2165.

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John D. Cook

3 years

A scientist ought to be accustomed to being proven wrong routinely. If not, what are they doing?

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John D. Cook

4 years

Some books are like a non-Newtonian fluid: they’re not especially dense, but they push back disproportionately hard if you try to go too fast.

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John D. Cook

6 years

Your most valuable skill may be something you don't even see as a skill. You think "Everyone can do that" but they can't. Maybe there's an intangible component that feels like 20% to you that feels like 99% to others.

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John D. Cook

2 years

Ask a room full of people to each roll a handful of dice and ask the ones with highest total to stand up. The ones who stand will have /something/ in common if you look hard enough. Maybe they have short hair, for example. ”Look: short hair is lucky!”

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John D. Cook

2 months

A video has gone viral that shows a professor making a gross probability error. The error he makes is based on a line of reasoning that is approximately correct in some circumstances. Explanation here:

Small probabilities add, big ones don’t

When can you get away with naively adding probabilities and when can you not? Why is this? What does it depend on?

www.johndcook.com

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John D. Cook

9 months

Jacques Ellul gives three reasons why intellectuals are the most susceptible to propaganda: 1. They take in the most second-hand information. 2. They feel the need to have an opinion on everything. 3. They believe they are immune to propaganda.

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John D. Cook

9 years

Technology has the shelf life of bread. Mathematics has the shelf life of honey.

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John D. Cook

1 year

@Ayegill

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John D. Cook

4 years

What terms like "known unknowns" mean

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John D. Cook

9 months

@Brad49649135 That’s why the Feynman lectures are amazing. Introductory physics from the perspective of a physicist with a Nobel Prize.

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John D. Cook

9 years

My contact info as a diagram. Idea stolen from @AllenDowney yesterday at #SciPy2015 http://t.co/ZX40dlgXm3

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John D. Cook

4 years

I've never heard a statistician say "Shut up. You're not a statistician." I have heard other people say just that, sometimes to statisticians.

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John D. Cook

8 months

This is a common pattern with bright students who have never before been asked to solve problems whose solution they can't see from the beginning.

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John D. Cook

4 years

I’m trying to read an article about how Microsoft Teams tracks you and how to block it, but in order to do so I must first agree to let Wired track me.

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John D. Cook

3 years

How Machiavelli described his book The Prince: “… in describing these monsters … I hope mankind will know them, the better to avoid them, my treatise being both a satire against them, and a true character of them …” Like 1984, intended to be a warning, not a blueprint.

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John D. Cook

3 years

Falsifiability is critical to science. If you react poorly to being proven wrong, being defensive rather than eager to learn, you’re not much of a scientist.

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John D. Cook

3 years

It’s easier to teach yourself programming than to teach yourself some other things because computers give immediate feedback. The difficulty with learning other things on your own can be the lack of correction. You can be wrong and not know it.

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John D. Cook

6 years

As AI gets better on average, the ways it fails get weirder.

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John D. Cook

3 years

Sometimes you just need to see something 20 times before you really understand it, but up to the 19th time you don’t know how close you are to your epiphany.

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John D. Cook

8 years

That awkward moment when you look at an ad and think "What have I done that some algorithm thinks I want to see this?"

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John D. Cook

8 years

"Nearly everything is really interesting if you go into it deeply enough." -- Richard Feynman

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John D. Cook

3 years

“Of all escapes from reality, mathematics is the most successful ever. It is a fantasy that becomes all the more addictive because it works back to improve the same reality we are trying to evade.” — Gian-Carlo Rota

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