The intersection of technology and leadership

Book Review: Quality Software Management: Systems Thinking

I’ve been interested in Systems Thinking explicitly for the last two or three years. I haven’t had many good books I could recommend to anyone other than “The Fifth Discipline.” Last year, I inherited a wealth of Jerry Weinberg books from fellow geek, Romilly Cocking and just got around to digesting a very classic book, Quality Software Management: Systems Thinking. Weinberg, whether or not you know it, has had a huge effect on our industry. He has written many books on wide ranging topics, and being a participant/organiser of the Amplify Your Effectiveness (AYE) conference continues to influence many leaders.

Anyway, back to the book.

Hard cover books are always a lot more intimidating than their soft covered brethren. Perhaps it’s the sheer bulky that does it. Fortunately the text is rather large and with only about 280 pages of content, easily consumed on a number of continental flights between the “no-electronic gadgets” zone.

I’ll admit that describing Systems Thinking is hard. Walking through, what Weinberg calls, Diagrams of Effects are intuitive when he explains them step by step, however I find it hard to describe the process and never have been very confident in some of the ones that I have used.

The Mechanics of Systems Thinking Diagrams
One tip that Weinberg talks about is thinking about the things in the boxes as things that you could measure (or you do measure) and their relationship between each other. Giving the item in a circle a name has been a challenge for me, and Weinberg presents a heuristic I feel I can make better use of.

Unlike models I’ve seen from places like Soft Systems Dynamics, Weinberg doesn’t use a plus or a minus, and maybe you’ll find his notations work for you. I can’t say they worked or didn’t exactly work for me. I did appreciate the different take on making the secondary, or implicit loops more explicit by attaching repeating loops to the lines they amplify, rather than to the entity they end up with.

In other Systems Thinking Diagrams, people sometimes note a delayed effect, something I was surprised didn’t really turn up in the book to a great deal. I don’t know whether or not this was intentional or not. A new difference I learned though was putting on another notation for diagramming where managerial decision/input affects the Systems Diagram. The way that Weinberg wrote about using this brought a little bit more of a humane aspect to it.

Repeating the role of Mental Models
In the Fifth Discipline, I didn’t really understand the importance of Mental Models related to the point of the Learning Organisation. After chatting to Mark Needham recently on the way that people interpret different things, and seeing how crucial this was to interpreting and drawing Systems Thinking Diagrams in Weinberg’s books, I better understand why these two things cannot be detached. In fact, it was very timely with the question that XP2011 keynote, Esther Derby kept asking, “In what world would this make sense?” to see things from a different Mental Model.

Weinberg tells a really good story about how these Mental Models effect the observation. He recalls a story talking to a manager who’s managed to work out how to distinguish good programmers from the bad ones. The manager starts talking about how he’s noticed how some programmers talk a lot to end users, or to other programmers. A grinning Weinberg, nodding at the manager’s observation slowly stops as he comes to realise how the manager don’t think of these inquisitive, communicative programmer’s as the better ones, unlike what Weinberg (and maybe you and I were thinking). Same observations, different interpretation.

Reconfirmation of in built human biases
We are full of biases that we aren’t even aware of. Many of Weinberg’s anecdotes remind me of some in particular. For example, he talks about how managers running projects that continue to fail, blame it on “bad luck”, or “something out of their control”, whilst taking personal credit for those that do succeed. This is a really good example of the Fundamental Attribution Error.

Things that didn’t work for me
Throughout the book, Weinberg refers to Pattern 1 and Pattern 2 type organisations. Even though he explained them early on in the book, I found it difficult to anchor any real meaning to them by the time I’d finished the book. I would have liked to have seen him give them better names and use them throughout. It’s a minor detail, however I did notice this slowing down my reading.

I’d recommend this, still highly relevant, book to people involved in IT today. Though it’s published in the early 90s, I’m surprised at how many of the stories are still relevant. It not only explains the basics of thinking with systems using models anyone can relate to. It also explains those systems diagrams that apply to the software problems of today.

1 Comment

  1. Serhiy Yevtushenko


    If you would like to really learn more about system thinking, I would recommend you looking to the system dynamics (and the following course on system dynamics –
    As well system dynamics allows formulating executable models (and there is a book on such models for software development)

    All the system thinking comes from Jay Forrester work (Peter Senge as well, has been member of Jay Forrester group) Concerning pattern 2 vs pattern 2 organizations – I believe here the CMM Level 1 (chaotic) vs CMM Level 2 could be used as analogy.

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