Goldilocks tests

I was speaking to my friend Allan Kelly at the Agile Cambridge conference and he mentioned he's reading a book about the maths of production. It contains a proof: rare failures that take a long time to fix are much much worse than frequent failures that get fixed fast. This is perhaps a counter-intuitive result to the way many people think. It may mean you'd be better off with more tests failing.

It's the goldilocks effect.
Is the porridge too hot or too cold or just right?
Are the beds too hard or too soft or just right?

Do you want tests always failing?
Do you want tests never failing?
Or do you want tests sometimes failing?

You want enough to give you some confidence that your tests are testing areas where defects exist. Because exist they surely do.
You want enough to keep the code current in the developers' consciousness. So they grok it. So they can fix fast.
You want enough to keep the developers' defect fixing skills sharp. So they can fix fast.

Backlog overwork is proportional to unused code?

A common problem I see in my travels is backlogs where items in the far future are excessively detailed. A subtle dynamic related to this overwork waste is that the more detail a developer knows about future stories the more likely they are to add extra "flexibility" for them into their current story development. And of course this contributes to the amount of unused code in the software (which is often quoted at averaging 45%). I therefore propose a hypothsis:

Backlog overwork is proportional to unused code.


is an excellent book edited by Anthony Kenny (isbn 0-19-287500-0). As usual I'm going to quote from a few pages:
We employ the word 'think' in two quite different ways; we talk of thinking about something, and we talk of thinking that something.
Intellectual activity, then, is regarded as in some way dependent on sense-experience; in some sense of the word Aquinas is an empiricist. Many empiricist philosophers have held that all our ideas arise from sense-experience, and that they are required by abstraction from or selective inattention to features of that experience.
When I look at myself in the mirror, I 'see' myself rather than seeing the mirror, unless I am making an especial effort to attend to the mirror.
A man cannot know what a whole is or what a part is except through the possession of concepts or ideas derived from experience.
A sense faculty which cannot go wrong is not a sense-faculty at all.
The oldest Oxford and Cambridge colleges were still in the future; just after Thomas was lecturing on the Sentences in Paris the delinquent baron, John de Balliol was ordered, as a penance, to found a house of scholars in Oxford.
As Wittgenstein once observed, it is not the answers which Aquinas gives, but the questions which he asks, which are the measure of his philosophical gifts.

Kierkegaard in a nutshell

is an excellent book edited Robert Van de Weyer (isbn 0-340-69404-1). As usual I'm going to quote from a few pages:
Kierkegaard ... says that most people avoid choice by living 'aesthetically', which broadly means relying on instinct and feelings.
In a provocative passage Kierkegaard suggests that boredom is the root of all evil. He contrasts boredom with idleness.
To Kierkegaard true freedom consists in overcoming constraints, because this involves choice and effort.
He did try to imagine a true 'knight of faith'; and his description is astonishing because the person he portrays is so ordinary... What marks him out is that he takes delight in every scene, every activity and every person. And even if something does not meet his expectations, he enjoys whatever transpires.
His consistent theme, that the source of truth is subjective experience, leaves little room for academic philosophy.
Far from being the root of all evil, idleness is the only true good. Boredom is the root of all evil, and so it must be kept at a distance. Idleness is not evil.
Boredom is overcome through being intensive in your interests, not extensive.
No moment should be regarded as so significant that is cannot be forgotten at your convenience. Equally each moment should have such significance that is can be remembered at will.
When you being to notice that a certain pleasure or experience is gaining too strong a hold on your mind, you should pause and reflect. This will make you want to stop the experience. From the start you should keep every enjoyment under control, never giving yourself totally to it.

Acting and thinking

I while ago I was waiting for the Reading to Heathrow bus and I got chatting to a very interesting lady called Suzanne from Germany whose son also has Aspergers Syndrome. For some reason I mentioned the Buckminster Fuller quote which goes something like:

It is is easier to act your way into thinking differently than to think your way into acting differently.

She said that thinking is a frontal cortex activity which is a relatively recent part of our brain, and that acting is done by much older parts of the brain. She also said that when there is fear the frontal cortex shuts down - we act using the older parts of our brain.

The deming route to quality

is an excellent book edited by William W. Scherkenbach (isbn 1-85252-363-8). As usual I'm going to quote from a few pages:
Anyone who stops learning is old, whether at 20 or 80. [Henry Ford]
There is real waste when people are always expected to have an answer.
The operational definition of any procedure is what you get when it is carried out, not what is written down on a piece of paper.
Someone must manage by the decade.
As with any process, if you focus on the outcome, you will not be competitive. You must focus on the process.
Management works on the system, people work in the system.
All models are wrong. Some models are useful.
The questions are always more important than the answers.
Dr. Deming frequently received calls from managers imploring him to 'come, spend a day with us and do for us what you did for Japan'.
Time and again I see the benefits of using a team.
Teamwork characteristics ... cannot be determined if you interview ... one at a time.

Toyota production system - beyond large scale

is an excellent book edited by Taiichi Ohno (isbn 978-0-915299-14-0). As usual I'm going to quote from a few pages:
There is nothing very complex in the magic of Mr. Ohno's teachings. In fact, it is often confusing listening to him because he talks so simply, often just saying to look for and eliminate waste. We cannot believe it is that simple - but it is true.
Henry Ford was able to mine iron ore on a Monday and, using that very same ore, produce a car coming off the assembly line on Thursday afternoon.
In the pull method, the final process withdraws the required quantities from the preceding process at a certain time, and this procedure is repeated in reverse order up through all the earlier processes.
The principal objective of the Toyota production system was to produce many models in small quantities.
Even worse, there would be no distinction between normal and abnormal states on each assembly line.
If materials or machines are repaired without the managing supervisor's being made aware of it, improvement will never be achieved and costs will never be reduced.
There is no waste in business more terrible than overproduction.
In modern industry, harmony among people in a group, as in teamwork, is in greater demand than the art of the individual craftsman.
In a swimming relay, a swimmer cannot dive before the previous swimmer's hand touches the wall.
I feel the most important point in common between sports and work is the continuing need for practice and training.
They would have had difficulty understanding the system without seeing it in action.
A half-hearted introduction of kanban brings a hundred harms and not a single gain.
Improvement is eternal and infinite.

Airplane kanban

My JAOO (now GOTO) SAS flight home from was slightly delayed. Over the tannoy, whilst we were still on the ground at Copenhagen, the captain explained it was because of early morning fog over Heathrow. He further explained that when its foggy air traffic control increases the gap between the planes in the air as they come in to land. This reduces the capacity and so to prevent a backlog of planes circling overhead they send out delays to planes so they take off a bit later. What this amounts to is that planes leaving can't take off until they receive a pull request from where they're due to land.

It helps to know what success looks like

On a plane when the cabin crew perform their emergency demonstration they don't merely read out the information over the tannoy. No. The cabin crew stand where you can see them. They act. You see them pulling an oxygen mask towards themselves. You see them putting it over their heads. If they're good you see them slowly turning their heads side to side so you can see the elastic at the sides of their heads.

One of my entries in the book 97 Things Every Programmer Should Know is called Make the Invisible More Visible. Visibility is an important aspect of practice and learning. It relates to feedback. You evaluate feedback in the context of your intention - of what you are trying to accomplish. You need a clear idea of where you are trying to get to, of what success will look like when you get there.

Do you have any post-its?

Developers love solving a solution. Unfortunately their eagerness can get in the way of understanding the problem. When I'm with a client I sometimes ask a simple question such as "Do you have any post-its?" I'm careful not to say I want some post-its. I simply ask if they have any. I could be asking the question because I think not-having post-its is an indicator of something else - in the same way that not-having whiteboards is an indicator of something else.

Often they start searching for post-its. I politely stop them and say that I don't want any post-its - I simply want to know if they have any. My aim is to increase their own awareness of solving the solution before probleming the problem.

The gift of time

is an excellent book edited by Fiona Charles (isbn 978-0-932633-75-0). As usual I'm going to quote from a few pages:
Jerry warns us that when a system that continues to change or that is in a changing environment is subjected to a fixed set of tests, it will inevitably over-adapt to those tests, leading to a higher probability of severe or surprising failures in the field. [James Bach]
Complexity isn't an attribute; it's a relationship. [Michael Bolton]
When feedback is offered in the spirit of improving a working relationship, it's all positive. [Esther Derby]
In my experience, if you have a passion for something and want to take responsibility for making it happen you can always find an existing group, or find people around you who are willing to form a new group to get it off the ground. [Willem van den Ende]
People are relentlessly themselves. [Naomi Karten]
In experiential learning, students are fully engaged, and as a result, they determine what they learn, not the instructors or presenters. [Naomi Karten]
...problems that look technical. [James Bullock]
Both PSL and aikido teach practiced awareness of oneself, the situation, and others. [James Bullock]
Shugyo is to step onto the mat exactly when there is every excuse not to. [James Bullock]
I have become enormously skeptical of simple cause-and-effect explanations of any system behavior. [Tim Lister]
And maybe most important of all (and I've been a consultant for about thirty years now), I thank Jerry for helping me think about system dynamics and change. [Tim Lister]
In the technology industry, we spend so much time trying to control machines that we start thinking like machines. [Jonathan Kohl]