Models and abstraction

My friend Kevlin Henney recently did a in-the-brain-of talk for SkillsMatter. He talked about Models and Modelling. Here's part of Kevlin's definition of a model

A model is an abstraction ... for a purpose.

There is an intimate relationship between a model and its abstraction. I think it was Andrew Koenig who said

Abstraction is selective ignorance.

The word 'ignorance' might mislead you here. It doesn't mean ignorance in the sense of an ignorant person - a person who should know something important but doesn't. It means ignorance in the sense of not being aware of something unimportant. The word 'selective' relates to the word 'purpose'. A clear purpose helps you decide what's important and what's not. Things that aren't important can then be omitted. Modelling is primarily an act of omission. The less clarity of purpose in your mind, the less omission is likely to take place, the more the model will try to say, without clarity.

The London underground tube map as a nice example of modelling. The usefulness of the tube map is directly related to the massive amount of omission in it (or should that be not in it?)

• it's not scaled - 5cm on the map does not relate to 5 miles on the ground.
• it's not proportional - stations 8cm apart on the map are not twice as far apart (on the ground) as stations 4cm on the map.
• it's not relative - stations north/south of each other on the map are not necessarily north/south of each other on the ground.
• it doesn't tell you street names.
• it doesn't tell you where the bus stops are.
• the turns in the River Thames are not all 90 degrees or 45 degrees.
• the little nicks on one side of the line don't tell you if the platform will be on the left or right.
• ...

These things are all omitted because they don't relate to the model's primary purpose - to help you get from one tube station to another tube station.

Things that a model does say should be said consistently. For example, the station names are all written horizontally, in the same font and style. If some were horizontal, some vertical, some slanted, some in black, some in blue, some large, some small, we might start wonder if the differences were significant. The model would be leading us astray. If the tube map was trying to be geographically accurate some parts of the map would get very squashed. The squashed stations might get a smaller font. And some might be angled into the only available space.

There is also at least one act of addition in the tube map. The lines have different colours. The circle line is yellow for example. Kevlin promises me that the steel tracks on the circle line are not yellow! But then again, perhaps the colour refers to the trains running on the track. Are the trains on the circle line noticeably yellow? If so, which had the yellowness first, the tube lines on the map or the actual trains? Or, over time, have they influenced each other?

It's easy to ignore just how much effort went into figuring out what to remove from the tube map. Wikipedia has a nice entry on how the tube map has changed over time. I remember once reading how Harry Beck spent years working on an early version of the tube map which his supervisor rejected because it needed to contain less.

A powerful abstraction helps you create a model of clarity, but the clarity can easily seduce you - you're not aware of all that has been omitted, and the effort needed to omit it. When you look at the tube map you just see the tube map.

Quality Software ManagementVol 1. Systems Thinking

is an excellent book by Jerry Weinberg (isbn 0-932633-22-6). As usual I'm going to quote from a few pages:

There is only one sin, and that's failing to believe you have a choice. [Jean-Paul Sartre]

A culture is a self-sustaining pattern that has remarkable powers of resistance to change.

The essence of a pattern is what it can do consistently.

When trying to introduce change in software engineering practices (or any practices, for that matter), it's often better to work by addition, rather than subtraction. Instead of continually emphasizing what people are doing wrong, emphasize what they are doing right so that they will do more of it.

The Reversible Fallacy: What is done can always be undone.

The Causation Fallacy: Every effect has a cause ... and we can tell which is which.

One of the most important tasks is not merely describing these laws, but in distinguishing which ones are "natural" laws that we'll have to learn to accept and which ones are "human decision" laws that we'll have to learn to control.

People's language often reveals when they believe that they are victims of events, rather than having a choice of reactions to the event. Learn to listen for falsely deterministic key words.

Any time you say, "I can't do that, " you'll always be right.

IQ scores would be a lot more meaningful if you added 10,000 to each score.

An hour of work is not an hour of work if you are interrupted during the hour.

The average defect detection time will keep rising throughout the project.

Poor quality hurts much more than good quality helps.

The software industry tends to focus on tools rather than on people.

The corporation

is an excellent book by Joel Bakan (isbn 1-84529-174-3. As usual I'm going to quote from a few pages:

"The corporation has essentially replaced the church in terms of who you are", says Edison Schools financier Michael Moe.

Indeed, the very notion that there is a public interest, a common good that transcends our individual self-interest, is slipping away. … These are the elements of an emerging order that may prove to be as dangerous as any fundamentalism that history has produced.

Socialism for the rich and capitalism for the poor, to borrow a phrase from George Bernard Shaw.

Most corporate law statutes include provisions that permit governments to dissolve a corporation, or seek a court order to dissolve it.

Corporations are our creations. They have no lives, no powers, and no capacities beyond what we, through our governments, give them.

We believe that some things are too vulnerable, precious, or important to exploit for profit.

The wisdom of crowds

is an excellent book by James Surowiecki (isbn 0-316-86173-1). As usual I'm going to quote from a few pages:

Diversity and independence are important because the best collective decisions are the product of disagreement and contest, not consensus or compromise.

The best way for a group to be smart is for each person in it to think and act as independently as possible.

To be smart at the top, the system has to be smart all the way through.

Adding in a few people who know less, but have different skills, actually improves the group's performance.

We have bad intuitions about averaging.

Keep the mistakes that people make from becoming correlated.

Information isn't in the hands of one person. It's dispersed across many people.

The problem starts when people's decisions are not made all at once, but rather in sequence.

People are more overconfident when facing difficult problems than when facing easy ones.

Encouraging people to make incorrect guesses actually made the group as a whole smarter.

Growing a business

is an excellent book by Paul Hawken (isbn 0-413-19340-3). As usual I'm going to quote from a few pages:

Be careful, you may succeed.

Gregory Bateson once defined the most elementary unit of information as the 'difference that makes a difference'. … The ability to create differences in manufacturing and delivery of goods and services will be the key to success.

Don't start two businesses.

Take a product and reduce it to its essence.

If employees, customers, and vendors don't laugh and have a good time at your company, something is wrong.

You don't ever manage people - you work with them.

Enterprises fail more often because of the sum total of seemingly inconsequential events acting upon them than because of a sudden disaster or discontinuity.

In the beginning, survival is more important than success.

Nothing in nature tells us that rapid growth is good, and certainly nothing in human biology. In our own bodies, the most rapid growth of all is cancer.

Businesses that grow too fast or in the wrong way overwhelm the adaptive capacity of the people who work there.

Responsibility is participation.

If a village in Europe or China wanted to censure and remove a member of its society, the townspeople went to the offender's home and burned it to the ground, along with all the possessions inside. That's how they fired someone.

Hire the person, not the position.

Linked

is an excellent book by Albert-László Barabási (isbn 0-7382-0667-9). As usual I'm going to quote from a few pages:

Mathematicians call this phenomenon the emergence of a giant component, one that includes a large fraction of all nodes. Physicists call it percolation and will tell you that we just witnessed a phase transition, similar to the moment in which water freezes.

What is the structure of the network encoding how the crickets, or people influence each other?

Power laws rarely emerge in systems completely dominated by a roll of the dice. Physicists have learned that most often they signal a transition from disorder to order.

Trapped between order and chaos, water molecules participate in a majestic dance in which some molecules come together, form small and somewhat ordered groups, move together, and in no time break apart to join other molecules forming yet other groups.

In the vicinity of the critical point we need to stop viewing atoms separately.

The theory of phase transition told us loud and clear that the road from disorder to order is maintained by the powerful forces of self-organization.

Errors and failures typically corrupt all human designs.

Computer simulations we performed on networks generated by the scale-free model indicated that a significant fraction of nodes can be randomly removed from any scale-free network without its breaking apart.

Innovations spread from innovators to hubs.

We need to understand living systems in their integrity.

Real networks are not static, as all graph theoretical models were until recently. Instead, growth plays a key role in shaping their topology.

Time wounds all heels

When I was a boy I was taught ITA spelling. ITA stands for Initial Teaching Alphabet. The idea was to teach phonetic spelling. As a consequence, despite years of ongoing effort and practice I still find myself misspelling homonyms - words pronounced the same but spelled differently. Words such as they're, their, and there. There (have to check it now...) are loads of them in English. I mentioned this to a friend on an email list a while back and he replied "What were they thinking?"
Quite.

Here's an example of how it can affect me - an anonymous quote I've read in two of Jerry Weinberg's books:

Time wounds all heels.

When I read this I just didn't get it. I knew I didn't understand it and I kept trying to. But to no avail. Why couldn't I understand it? Answer: because I was reading it as:

Time wounds all heals.

The word wounds was nudging my ITA brain to see/hear the word heel as heal. They naturally fit together as opposites after all! And of course in reverse it is heal - Time heals all wounds.

How did time suddenly heal my wound and reveal the true meaning to me? It was while I was attending Jerry Weinberg's Problem Solving Leadership course. Jerry was talking about "Time wounds all heels" and he simply said the words "Achilles" and "heel" one after the other. And in that moment I understood! Heel. Heel. Not Heal. Time wounds all heals. Damn. I did it again. I really did. Time wounds all heels. Your (that's one I've learned I have to check... no it's not you're) Achilles heel is your (again) weak (not week) spot.

Switch - how to change things when change is hard

is an excellent book (isbn 978-1-84-794031-5). As usual I'm going to quote from a few pages:

What looks like a people problem is often a situation problem.

Psychologists have discovered that self-control is an exhaustible resource... What looks like laziness is often exhaustion.

What looks like resistance is often a lack of clarity.

TBU - true but useless.

Knowledge does not change behaviour. We have all encountered crazy shrinks and obese doctors and divorced marriage counsellors.

To be clear, it's not so much that you're a brilliant predictor; it's that he's a lousy self-evaluator. We're all lousy self-evaluators.

When milestones seemed to distant, they should look for "inch pebbles".

Coaches are masters of shrinking the change.

Stanford psychologist Lee Ross... noted that people have a systematic tendency to ignore the situational forces that shape other people's behaviour. he called this deep-rooted tendency the "Fundamental Attribution Error."

With hard goals, action triggers almost tripled the chance of success.

We are not nouns, we are verbs

Stephen Fry was interviewed in this weeks Radio Times. The following snippet caught my attention:

Oscar Wilde said that if you know what you want to be, then you inevitably become it - that is your punishment, but if you never know, then you can be anything. There is a truth to that. We are not nouns, we are verbs. I am not a thing - an actor, a writer - I am a person who does things - I write, I act - and I never know what I am going to do next. I think you can be imprisoned if you think of yourself as a noun.

When things start to think

by Neil Gershenfeld is an excellent book (isbn 0-340-75039-1). As usual I'm going to quote from a few pages:

The fibres that make up a sheet are actually translucent. Light striking the paper gets bent as it passes through a fiber, and since there are so many fibres this happens many times in many directions. The result of all this scattering is that the light spreads through the paper much like the spread of a drop of ink, eventually leaking back out. ... This phenomenon, called optical weak localization, is what makes the paper (or a glass of milk) appear to be white.

There are deep reasons why the old technologies in a book work so well... What jumps out the first time you see a Gutenberg Bible is the glossiness of the ink. It turns out that Gutenberg made his inks by cooking a stew of oil and copper and lead that precipitated out little platelets that act like tiny mirrors, paradoxically reflecting light from a black background.

Freed from the constraint of duplicating manuscripts, Aldus Manutius in Venice around 1500 then settled on the dimensions of the modern book. It was designed to fit in the saddlebags of traveling scholars, and his Press developed the italics font, to fill the pages more efficiently than did fonts that imitated handwriting.

If you're offered a better computer program, it's not possible to peer inside and judge how it works.

It requires great discipline to put just enough of the right kind of information in the right place to communicate the desired message rather than a printer demo.

Like all good scientific discoveries, the seeds of Lorenz's observation can be found much earlier.

Good help is as hard to find in the digital world as it is in the real one.

Naming the solution is not the same as obtaining it.

It's all too easy to defer thinking to a seductive computer program.

The brain's internal representation is not designed for external consumption.

The world is the next interface.

It's often a situation problem

In a previous blog post I commented on a recurring theme in several software classics - the idea that it's always a people problem. I was reminded of that sound-byte today while reading Switch - How to change things when change is hard by Chip and Dan Heath. Their surprising-thing-about-change number 1 (of 3) is

What looks like a people problem is often a situation problem.

I prefer this version, partly because it uses the word often rather than always and so it follows Bill Bailey's Law. But mostly I prefer it because saying "it's always a people problem" feels demotivating because we are all people and you get drawn into thinking you're the problem. As Deming made clear, the root cause of most problems is not the people but the system. But the word "situation" is simpler and somehow easier to grasp than "system". It's clear your always in the situation that you're in.

A related quote from Switch is

to change someone's behavior you've got to change their situation.

I like this a lot and it reminds me of the various quotes about acting your way into thinking differently being easier than thinking your way into acting differently...

Sometimes it’s easier to act your self into a new way of thinking, than it is to think your self into a new way of acting. (Jo Berry)

You cannot change how someone thinks, but you can give them a tool, the use of which leads them to think differently. (R. Buckminster Fuller - quoted in The Fifth Discpline by Peter Senge)

Adults are much more likely to act their way into a new way of thinking than to think their way into a new way of acting. (Richard Pascale's in Surfing the Edge of Chaos)

Or, to say it in reverse

Knowledge does not change behavior.

So instead of saying "it's always a people problem" perhaps it is better to say "it's rarely a people problem"

Gandhi an autobiography

is an excellent book (isbn 978-0-141-03273-3). As usual I'm going to quote from a few pages:

All his life he held to two fundamental principles, a belief in Ahimsa, or non-violence, and the concept of Satya, or truth; as he said: 'My uniform experience has convinced me that there is no other God than Truth.'

Renunciation of objects, without the renunciation of desires, is short-lived, however hard you may try.

Jealousy does not wait for reasons.

I had been advised to collect certificates of my having abstained from meat, and I asked the English friend to give me one. He gladly gave it and I treasured it for some time. But when I saw later that one could get such a certificate in spite of being a meat-eater, it lost all its charm for me.

Experience has taught me that silence is part of the spiritual discipline of a votary of truth.

Great men never look at a person's exterior. They think of his heart.

Rest assured it takes no unusual skill to be an ordinary lawyer. Common honesty and industry are enough to enable him to make a living. All cases are not complicated.

I scrupulously avoided hurting their feelings.

It went against the grain with me to do a thing in secret that I would not do in public.

The heart's earnest and pure desire is always fulfilled.

Service can have no meaning unless one takes pleasure in it.

Long Walk to Freedom

is an excellent book (isbn 978-0-349-10653-3). As usual I'm going to quote from a few pages:

I maintain that nurture, rather than nature, is the primary moulder of personality.

I did well in school not so much through cleverness as through doggedness.

These [meetings] were not scheduled, but were called as needed... Everyone who wanted to speak did so... People spoke without interruption...

Majority rule was a foreign notion. A minority was not to be crushed by a majority.

This metal wire, he said, pointing above, is an example of Western manufacturing, which is skilful but cold, clever but soulless.

I could compensate for lack of natural aptitude with diligence and discipline. I applied this to everything I did.

There is nothing like returning to a place that remains unchanged to find the ways in which you yourself have changed.

Gaur believed in finding solutions rather than spouting theory.

I was far more certain in those days of what I was against than what I was for.

If fine bodies and impressive physiques were essential to being a leader, I saw that few among us would have qualified.

If you wait for textbook conditions, they will never occur.

Class, Nyerere always insisted, was alien to Africa; socialism indigenous.

I did not think this view [always rejecting bail] should be universally applied and believed we should examine the issue on a case-by-case basis.

Any man or institution that tries to rob me of my dignity will lose because I will not part with it at any price or under any pressure.

cyber-dojo server is up

The first cyber-dojo server is up, at http://www.cyber-dojo.org Please note the hyphen - the url without the hyphen was not available. The infrastructure is very very very rudimentary, but it's a start. Something to learn from and build on. Any feedback always welcome.

Have you got any strawberries?

I was driving along the A303 towards Gatwick last week and passed several stalls selling strawberries. It reminded me of an incident many years ago, before the kids were born, on the same road when Natalie and I stopped to buy some. We approached the stall. The only thing it sold was strawberries. It was a strawberry stall. Everywhere you looked here were open punnets of strawberries. With a twinkle in my eye I looked at the two young lads manning the stall and watched their puzzled faces as I asked "Have you got any strawberries?"

The World's Least Favourite Airline?

I had a great family cruise on NCL's Norwegian Gem visiting Venice, Dubrovnik, Izmir, Athens, and Nafplion. I particularly liked Dubrovnik and the ruins at Ephesus are truly spectacular and were well worth the long taxi ride from Izmir. NCL was faultless in all respects and I have no hesitation wholeheartedly recommending NCL, it's cruises and its staff.

But not British Airways…the BA flight home from Venice to Gatwick was a joke. There were numerous check in desks at the airport and the only one with a sizeable queue was BA's. In fact the BA queue was so long it blocked one side of the building from the other. I looked (and asked) for some self-service check-in desks and found quite a few from many airline companies but none from BA. The day's first flight from Venice to Gatwick was so late we got to see the end of that fiasco too. It was over-booked and several people queued for two and half hours in sweltering heat only to fail to get a boarding pass. These people naturally joined the queue for the next flight so that flight was overbooked too. But did anyone walk along the queue offering cash to anyone willing to take a later flight? No. So once again some people at the end of the queue were going to fail to get a ticket after queuing for several hours. While the first flight's queue was queueing security had to be called because everything was so badly organised. As usual one of the check-in desks was reserved for Club-something-or-other and so sat mostly idle while the queue lengthened and people grew more and more irate.

We were on the second BA flight out. Having seen the problems from earlier in the day we joined the queue very early. It was a wise move as the queueing was just as badly organised. Eventually we got to the check-in desk and just after we had got our boarding passes I happened to see a not-so-easy-to-see note offering €250 if you took a flight the next day. And just after we had got our boarding passes the check-in lady told us the flight was delayed for an hour - which of course meant it would be delayed for more than one hour - why do they always underestimate the delay? If we had been told the flight had been delayed before we started checking in we might well have taken the offer. We certainly would have given it some serious consideration. And why if they know it's an hour late don't they show that information on the departure boards?

It would have been so easy for BA to do the little things that showed they cared about their customers. Something as simple as providing some kind of cool drink for people while they queued in the heat. It wouldn't be much, but it would be something and it would change the situation so completely. But no.

Over and over you felt BA simply didn't care about you.

I fly quite a lot and from now on if I have a choice - and on several routes I do - I'm not going to fly BA.

The Autobiography of Andrew Carnegie

is an excellent book (isbn 0-451-53038-1). As usual I'm going to quote from a few pages:

In an incautious moment my parents had promised that I should never be sent to school until I asked leave to go. This promise I afterward learned began to give them considerable uneasiness because as I grew up I showed no disposition to ask.

He is a bold man who calls anything a trifle.

The fundamental advantage of a library is that it gives you nothing for nothing. Youths must acquire knowledge themselves.

The celebrated maxim of Confucius: To perform the duties of this life well, troubling not about another, is prime wisdom.

Whenever one learns to do anything he has never to wait long for an opportunity of putting his knowledge to use.

How reserved the Scot is! Where he feels most he expresses least. Silence is more eloquent than words.

Slight attention or a kind word to the humble often bring back reward as great as it is unlooked for. No kind action is ever lost.

Even in these days of the fiercest competition, when everything would seem to be matter of price, there lies still at the root of great business success the very much more important factor of quality.

No sound judgement can remain with the man whose mind is disturbed by the mercurial changes of the Stock Exchange. It places him under an influence akin to intoxication. What is not, he sees, and what he sees, is not.

Mr Pullman replied: "Yes, my friends, all that you say is true. I have had a long, long life full of troubles, but there is one curious fact about them - nine tenths of them never happened."

Trondheim XP Agile cyber-dojo

Anders Hammervold and Jonas Follesø organized a cyber-dojo for the Trondheim XP Agile group yesterday. Anders tells me great fun was had by all.

Managing the design factory

is an excellent book by Don Reinertsen (isbn 0-684-83991-1). As usual I'm going to quote from a few pages:

Best practices are only "best" in certain contexts and to achieve certain objectives. A change in either the context or the objective can quickly transform a "best practice" into a stupid approach.

We must constantly remember that the simplification [of the abstraction] is a veil between us and the reality of the process.

Manufacturing is an inherently repetitive process and therefore more likely to produce learning than a non-repetitive process, like product development.

In the design process we can only add value when we do something differently. If we change nothing, then we add no value.

We will see much more variability in the design process than we see in repetitive manufacturing process. This variability is an indicator that we are doing something new in the design process, and thus that we are adding value.

Risk and the variability associated with it, are inherent and desirable characteristics of design processes. They are at the heart of a design process's capacity to generate information.

The design factory needs variability, so it needs tools that allow us to coexist with variability.

When you dig below the surface you discover that most change programs are motivated by two forces: imitation and obedience.

Events that are less probable contain more information.

Our testing processes need to have an adequate failure rate to generate sufficient information.

Each iteration starts on the base of the quality of the previous pass.

A process is a way of preserving learning that occurs when doing an activity.

A whirlwind at Reading station in 1840

As well as the super statue of the World War I soldier at Paddington by my namesake I also spotted this at Reading station last week. It's on platform 4 but you have to look quite hard to find it.