Presenter: Laurent Bossavit


  • to gain exposure to systems thinking ideas in general
  • to learn about Diagrams of Effects in particular
  • to consider empirical applications of DOEs
  • to be able to establish meaningful measurements on software projects


How do you figure out where to start with XP practices ? How to tell which practices should be used together, which can be safely set aside to begin with ? How to predict the consequences, good and bad, of changing your software development processes ?

These questions often confront managers new to XP or Agile processes. It turns out that there is a methodic and rigorous way of dealing with them, first popularized by Willem van den Ende and Marc Evers (XP 2004, Agile2006, etc.). Arising from the discipline known as "Systems Thinking", the use of Diagrams of Effects or Causal Loop Diagrams to understand the dynamics of software projects has, by now, become a standard tool in effective XP/Agile coaching.

In a Diagram of Effects, the basic entities are modeled as circles ("measurable" aspects of the system) or clouds (aspects of the system which are only "quantifiable", i.e. could be represented by a number in principle, but might be hard to measure in practice). Cause-effects relationships are modeled as arrows: an arrow between "Bug count" and "Customer satisfaction" is read as "Bug count has an effect on customer satisfaction". That's (almost) all there his to the DOE notation. Because of this simplicity, a team using the tool can rapidly discover important dynamics in its own processes.

This session aims to give a recap of the DOE tool, and will therefore benefit even people who are unfamiliar with DOEs. I aim to go further than previous sessions on this topic by showing how DOEs can be more than a conceptual tool, and can in fact be used to verify, empirically, whether Agile practices will work in your context. Participants will group by work affinities and explore an actual situation using the DOE tool.

I will end (5') by introducing SimProject, an exploratory project aiming at actual numerical simulations based on system structures described initially from DOEs, and demo at least one simple system structure in SimProject, and suggest other practical applications of systems thinking.

Format and length: 90 minutes workshop