Approximate And Exact Answers

October 17, 2020

Seen on the (data visualisation) Edward Tufte site:

You have already quoted a short version of John Tukey’s aphorism, but I prefer a slightly longer expression of the same idea that he wrote in 1962:

Far better an approximate answer to the right question, which is often vague, than an exact answer to the wrong question, which can always be made precise.

Somewhere he also wrote (but I’ve been unsuccessful in tracking down where or when I read it),

If a thing is not worth doing at all, it is not worth doing well!

MIT Course On COVID And The Pandemic

September 4, 2020

I’ve been interested to take a (free) online course for a while now and was waiting for a subject that really engaged me. This one from MIT on a key topic of the day, COVID and the Pandemic, looks really good. The first lecture is up on the site with more to follow (the second one is advertised above). You can watch live if time zones allow (see below).

I’m interested partly due to the content but also to see how complex science material is presented these days (communication and engagement).

From the MIT course site:

“Course description: Lectures by leading experts on the fundamentals of coronavirus and host cell biology, immunology, epidemiology, clinical disease, and vaccine and therapeutic development. This is an exploratory subject, open to undergraduate and graduate students…

The class is open to all MIT students, as well as any eligible cross-registered students. The live stream will be available to the public, but only registered students may ask questions during the Q&A.To view the live stream, click on this link and type in the password: mit-covid. Miss a class? You’ll be able to view a video of the lecture on this page. Please note: It will take a few days to caption and post each lecture video after the livestream has ended.”

Giving Smart Answers Under Pressure

August 24, 2020

I recently decided to sell my vinyl collection, lovingly kept for years. The traditional hi-fi takes up too much space, changing sides of albums is a chore and (the way it’s set up) it’s primarily for just one room. I now find Sonos and Spotify (and others) a much more flexible and convenient arrangement. I’m not bothered by the slight decrease in sound quality. The latter also allows easy search for known artists and it’s fascinating to discover loads of great new musicians I never knew existed.

For selling the vinyl (that I had an obvious emotional attachment to), I had to come to a rough valuation. As I was moving house at the time and things were hectic, in the end I didn’t pay too much attention to this. I did find sites that gave estimates for individual prices (depending on their condition and the pressing) but going through the whole collection would have taken ages. Also there were comments that the prices were very subjective. So to get a quick solution I did some very rough guesswork and negotiated from that.

What I should have done (obvious in hindsight) was do some guesstimates. At the very least, put records into categories (rock, folk, jazz and classical), estimate average prices plus identify any special items of value which presumably would be few eg early pressings. This valuation is not what you may achieve but at least gives a better starting point to negotiate from. As they say, in negotiations, the one with most knowledge wins! The issue is what is the smartest thing you can do under strict time pressure. I’m not saying I got a bad price it’s just that I’d have a nicer feeling inside if I’d thought things through (I know, that’s life!).

This got me thinking about more general guesstimates, sometimes called Fermi Problems or back-of-the-envelope calculations. Fermi was a highly creative scientist and won the Nobel Prize for his ground breaking work in nuclear physics. He was one of the last ‘giants’ that could encompass and contribute to both experimental and theoretical physics (disciplines that require very different skills). He had a reputation for his seemingly uncanny ability to give good estimates to tricky problems even with little actual data.

A famous example of a Fermi Problem (that he used to tantalise students with) is: How many piano tuners are there in Chicago?

This at first site seems an impossible problem but on reflection some educated guesses can be made that give a good approximation to the answer (see here):

  1. Assume population of Chicago is roughly 3,000,000 (actually 2,693,976 in 2019)
  2. Assume average family size is 4, so number of families is about 750,000
  3. If one in five families owns a piano (seems a bit high but rounds things for easy calculation), then 150,000 pianos to be tuned in principal
  4. If the average piano tuner works 5 days a week and tunes 4 pianos a day for 50 weeks a year (2 week vacation), he/she can service 1,000 pianos.
  5. So, for these two estimates to match, there must be about 150 piano tuners in Chicago.

Obviously you can contest each assumption, see how sensitive it is to changes and so on. But the main point is that some simple and quick reasoning can give an initial ball-park figure (ie order of magnitude 100 tuners). You’re now working from a situation of some knowledge rather than no knowledge.

Recently I came across a site, Street of Walls, that goes through a number of these problems in a business setting. For instance, they might be the sort of question you get in a demanding job interview for management consultancy.

Examples they give (with typical ‘answers’) include:

  • How many flat screen televisions have been sold in Australia in the past 12 months?
  • How many iPhones are currently being used in China?
  • What is the revenue of Peugeots sold in France per year?

These questions might all sound crazily difficult but using the approach of the piano tuner example above, it might be educational to try the above questions prior to looking at the answers. Remember, you’re not looking for ‘the’ answer rather a reasonable and quick approximation to it. In some sense, this is the first step, to reframe the question into something manageable. Also, to keep your cool.

This approach to developing intelligent guesses also reminds me of something that the famous physicist Richard Feynman said (and probably many others too). When you start a problem make some bold educated guesses. If a more careful analysis gives a very different answer, figure out what you missed in the back-of-the envelope approach and try to learn from it. With a bit of luck, your intuition and guesswork will steadily improve and deepen as a result.

I’ve written about the topic of guesstimates previously, motivated by some thoughts of Seth Godin:

“When I interview people for jobs, I always ask, “How many gas stations do you think there are in the United States?” Not because I care how many gas stations there are, but because it gives me an insight into how people solve problems.

The vast majority of people who answer this question (Iʼve asked it more than 1,000 times over the years) start their answer with, “Letʼs see…there are 50 states.” They then go on to analyze their town, figure out how many gas stations there are, and multiply from there…”

He mentions this is not a good approach as it doesn’t deal with easily scalable quantities and ends up with another totally different way forward:

“Instead of starting the business that makes stuff for people just like you, do some real re-search. Go to the library. Donʼt invent something that requires you to have a handle on the purchasing habits, the psychographics, and the changing demographics of the whole country. Instead, find a thriving industry and emulate and improve on the market leader. Sheʼs already done your homework for you.”

This could be an additional point you could use in the interview. More details in my original post here.

Finally, as an aside, on the topic of extremely demanding and somewhat crazy interview questions, see here.

You Forget What You Know (Gell-Mann Amnesia)

May 30, 2020

“Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray’s case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the “wet streets cause rain” stories. Paper’s full of them.

In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.” – Michael Crichton (author and filmmaker, 1942-2008)

That’s a really good observation.

As an aside, Murray Gell-Mann was  an influential theoretical physicist who was awarded the Nobel Prize in Physics in 1969 for his work on fundamental particles. He was based at the California Institute of Technology and later went on to co-found the famous Sante Fe Institute (for the study of complex systems).

He and the more well-known Richard Feynman were famous collaborators and later ‘rivals’. I’ve written quite a few posts on Feynman (two of the most popular are here and here).

There’s an illuminating talk by Gell-Mann on Edge (The Making of a Physicist) and a very well-wriitten biography if you’d like more details. From the former, an interesting and somewhat provocative quote:

“Dick (Feynman) and I had different talents. His great talent was for finding marvelously clever mathematical tricks for expressing theories in physics and then solving problems using those tricks, which always involved a great deal of physical insight. He was less good at finding new physical theories and getting them right, whereas I seem to have had a talent for finding out what was going on and guessing the right theory.”

Revisiting Imperial College London

June 13, 2019

The main entrance to Imperial College London

Recently I went to Imperial College to hear an Athena lecture by Margaret Heffernan on Scientific Leadership. This lecture is given annually by a prominent female scientist or entrepreneur to celebrate the achievements of women in science, technology, engineering and medicine. It should be on YouTube soon and I’ll put a link up and make some comments about it then.

This year I became an Alumnus of Imperial College (having got my doctorate there many years ago). I’m keen to get involved in one way or another so attending the lecture was a good start as it allowed me to have a look around to see how the College has changed. Here’s some photos that give a flavour, showing the modernisations, two famous physicists I knew and the delightful and surprising mews area nearby.

The impressive Faculty Building

The Bessemer Building (Engineering)

I decided to go to the Physics Department where I spent 3 years of my life carrying out research for a doctorate in theoretical high energy physics. The head of the theory group at that time was Tom Kibble (who ‘almost’ got the Nobel Prize for Physics in 2013). Abdus Salam, who was co-awarded the Nobel Prize in 1979, was also there as he held positions at the International Centre for Theoretical Physics in Trieste, Italy (which he helped set up) and Imperial. It was an especially exciting time to be doing research as a lot of breakthroughs were made in understanding the fundamental particles and their interactions (quarks, the Higgs boson etc).

I’ve previously written about an interesting conversation I had with Salam that sparked my interest in giving advice and following different paths in life. The point being that when someone makes a suggestion that’s not in your current plans, it’s quite hard to really appreciate it or take advantage of it. However not doing so might be the loss of a major if unconventional opportunity (more details here).

Professor Abdus Salam (Nobel Prize for Physics 1979)

Professor Tom Kibble

Not far from the hustle and bustle of the university are a number of delightful mews. I have a memory of a small pub which we used to drink in in this area. I tried to track it down but to no avail. Perhaps it had been changed into a house or perhaps my memory was mistaken.

A delightful mews very near to imperial College

Another nearby mews

In hindsight, it was quite a privilege to be at Imperial at this time, great people and a wonderful location.

Risk versus Uncertainty

March 21, 2019

From the FT recently, on the difference between risk and uncertainty, and its implications:

“It (the distinction) was first made back in 1921 by the University of Chicago economist Frank Knight. Risk, he said, is something we can quantify, as when we say there’s a one-in-six risk of a die rolling a one. Uncertainty, however, cannot be quantified…

The biggest uncertainty is: technical change. Only one in eight of the US’s largest 500 companies in 1955 are still in the largest 500 today. And only two of the UK’s largest employers in 1907 are independent stock market-listed companies today: Prudential and WH Smith.

Herein lies a big difference between risk and uncertainty. Some risks diminish over time as losses are followed by gains…

Uncertainty, however, increases with time. We have a fairly good idea of the strengths, weaknesses, opportunuties and threats facing a particular company over the next 12 months. But if we’re honest, we haven’t a clue about them over the next 30 years.”

In this context it’s revealing how tricky it is to forecast long term change, say through research planning, see here.

Famous Physicists At Cambridge

February 26, 2019

St John’s College at Cambridge (UK)

I recently paid a visit to St John’s College at Cambridge (see above). One evening we had dinner in the impressive Great Hall. Afterwards I took at the look at the portraits on the walls of past Fellows.

Paul Dirac, Fellow of St John’s

I knew that Paul Dirac (one of the world’s greatest theoretical physicists) was a Fellow but I was quite surprised to see a portait of Abdus Salam as well who I didn’t know was a Fellow. Abdus Salam was awarded the Nobel Prize for Physics in 1979 along with Steven Weinberg and Sheldon Glashow.

Abdus Salam, Fellow of St John’s

I’ve given a story (see here) about a discussion I had with Salam (who was then a Professor at Imperial College London) that made me realise the skill and awareness needed to take unconventional career advice.

St John’s has impressively produced nine Nobel Laureates (five in Physics, two in Medicine, one in Chemistry and one in Economics, see here).

The Iceberg Illusion

September 11, 2018

Something to reflect on and always bear in mind! Sylvia Duckworth is an award-winning teacher from Canada and uses sketchnotes (as above) extensively.


Feynman and Climbing Mont Blanc

August 28, 2018

Poster for a current Caltech Archives special exhibition on the occasion of the 100th anniversary of Richard Feynman’s birth (1918-1988)

I’ve written previously (see here) on how the famous physicist Richard Feynman figured out how to get out of a creative block that occurred after his initial revolutionary successes (for which he was awarded the Nobel Prize in Physics in 1965):

That’s what I’d forgotten!” he shouted (in the middle of the night). “You have to worry about your own work and ignore what everyone else is doing.” At first light, he called his wife, Gweneth, and said, “I think I’ve figured it out. Now I’ll be able to work again!”

However recently I came across an article by John Preskill of Cal Tech which mentions another viewpoint attributed to Sidney Coleman (who was a Professor of Theoretical Physics at Harvard University). Preskill is the Feynman Professor of Theoretical Physics at Cal Tech:

Feynman often told students to disregard what others had done, to work things out for oneself. Not everyone thought that was good advice. One who disagreed was Sidney Coleman, a Caltech grad student in the late 50s and early 60s. Coleman says: “Had Feynman not been as smart as he was, I think he would have been too original for his own good. There was always an element of showboating in his character. He was like the guy that climbs Mt. Blanc barefoot just to show it could be done. A lot of things he did were to show, you didn’t have to do it that way, you can do it this other way. And the other way, in fact, was not as good as the first way, but it showed he was different. … I’m sure Dick thought of that as a virtue, as noble. I don’t think it’s so. I think it’s kidding yourself. Those other guys are not all a collection of yo-yos. Sometimes it would be better to take the recent machinery they have built and not try to rebuild it, like reinventing the wheel. … Dick could get away with a lot because he was so goddamn smart. He really could climb Mont Blanc barefoot.” 

There are lots of nice stories and insights in the Preskill article (entitled ‘Feynman After 40’) which is well worth a read.

Grand Challenges and Anticipating the Future

August 22, 2018

I met up with a colleague recently who works in the transport area and she recommended I take a look at a couple of articles including (for general context) the UK Innovation Strategy. The document detailing this (published in Nov 2017) can be found here, including:

“As well as setting a path to improved productivity, our Industrial Strategy sets out four areas (Grand Challenges) where Britain can lead the global technological revolution.”

It’s interesting to consider these big picture themes as it’s all to easy to get locked into details in specific projects.

The Four Grand Challenges are (plus some further explanatory extracts, see here):

1. Artificial intelligence and big data

They can be seen as new industries in their own right, but they are also transforming business models across many sectors as they deploy vast datasets to identify better ways of doing complex tasks – from helping doctors diagnose medical conditions more effectively to allowing people to communicate across the globe using instantaneous speech recognition and translation software.

2. Clean growth

The move to cleaner economic growth – through low carbon technologies and the efficient use of resources – is one of the greatest industrial opportunities of our time. By one estimate, the UK’s clean economy could grow at four times the rate of GDP. Whole new industries will be created and existing industries transformed as we move towards a low carbon, more resource-efficient economy.

3. The future of mobility (people, goods, services)

The UK’s road and rail network could dramatically reduce carbon emissions and other pollutants, congestion could be reduced through higher-density use of road space enabled by automated vehicles, and mobility could be available when we want it, where we want it and how we want it.

4. Meeting the needs of an ageing society

The prospect of longer lives will require people to plan their careers and retirement differently. Ageing populations will create new demands for technologies, products and services, including new care technologies, new housing models and innovative savings products for retirement.

The first three you could see as predominantly technological challenges but the fourth is far more complex as it will need to take into account inter-generational attitudes and mindsets. A good example of a cross-disciplinary project.