The Unvexing

This post comes to you courtesy of Graham Lee at: http://www.sicpers.info/2016/11/the-vexing-problems-in-programming/ who reminded me about Value. We agilists (people who believe in agile software development) talk about value a lot but haven’t  agreed on a consistent definition of the word. As an illustration of two of the options:

“The value of this car is £9,500.” Is that to a seller or a buyer? Unless there is a difference, no trade will take place. Or is it a market rate? The long acquisition dance between Yahoo! and Google makes an interesting case study. This is: a value. A ‘fact’, right or wrong. It is the kind of thing developers in imperative programming languages put into variables and mutate but pure functional programmers squirrel away for ever, to embarrass themselves at their past Wrongness.

In contrast, “This car cost £9,500 pounds. I think that was quite good value but the model that costs £1,000 more is even better value.”, is a relative benefit:cost calculation, yet the manufacturer may market a ‘value’ model, which is just cheap. This is: a value judgement. An explicit or implicit comparison relative to something else, followed by a decision. It is a computation.

When Graham says, the most vexing problem of software product  developers is their inability to “compare the expected value of their work to the expected cost of the work.”, I think he means  ‘business benefit of their work’, and cost normally equates closely to development time. All the customer really wants to know is: “Is this the best investment I could make now?”

Graham goes on to say that we are very bad at estimating how long something will take. This is true but we are much better at estimating small jobs accurately than large ones.  Uncertainty increases exponentially with length of sequence of actions, to slightly corrupt Shannon’s Information Theory. This is why the Fibonacci sequence is often used as a sizing tool.

Agility accepts this reality. It addresses the list of things the customer currently wants, in highest benefit:cost ratio order (guessed by a business domain expert, based on guesses by an agile develooment team.) It doesn’t yet know whether the ‘whole job’ is worth doing. It decides only whether to risk the next small, cheap step and keeps doing that, as long as the ‘value’ is Good Enough. While value is high and risk is low enough, keep going.

A journey of any length starts with the first step, so why worry about whether or not it is going to be 1000 Miles? The hard part is to make it a journey, rather than simply wandering about, lost.

Then there are: our values. Our personal decisions about what matters most to us. Do we go home to read our children a bedtime story or work late and win that promotion so they have greater financial security in the future? What do we really care about and what are we willing to pay for it? This too is relative. Politics is the art of persuading you to modify your personal values. Currently, cheating is allowed.

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