You’ve probably seen these. You may even have created one.

They are the big, colorful diagrams which sit over the desks of some modellers. They have loads of boxes, even more lines, and they are designed to say one thing.

“Look at me”

Silly big diagramIf they were just a harmless exercise in drawing, they wouldn’t be so bad. But you just know that they took someone hours and hours and hours to create. And someone paid for all that time

Ah! you say. But the modeller needed this big diagram to give them an overall picture of what’s happening. But does it? Can you really look at this diagram and see where something is missing? The example above is from the OMG’s BPMN modelling language, and is one of their demonstration examples, presumably to show what a great thing BPMN is. But it’s a hopeless way of conveying information  – which is one purpose of such a diagram – and shows lazy modelling. By lazy, I mean intellectually lazy. Not time-lazy, as it clearly took ages to create. The modeller chose not to use their knowledge and experience to chop the diagram into bits, so they they and their readers would have a chance of spotting the gaps, overlaps and inconsistencies. Because this is what we’re supposed to be doing.

4 ways to spot you have a ‘look at me’ diagram

  1. You’re starting to feel that printing the diagram and putting on the wall near your desk will enhance your chances of promotion
  2. You’ve spent a hour on the internet looking for a device driver which will let you print it on a giant printer
  3. You found the driver, but not the giant printer, but you did find lots of sticky tape and glue in the stationary cupboard, so now you’re having loads of fun joining the bits together
  4. If you print the diagram as A4/Legal size, the writing is only visible with a electron microscope.

..and what to do about it

  1. Chop it into pieces.

That’s it. Simple. Well, not always. But this where we show our modelling skills. We’re the ones who are supposed to be able to pull all this knowledge into our heads, and write down a set of smaller, easier diagrams, which help a reader to work they way into the problem. This is our job.
More on ‘how to make diagrams readable’ in future posts.

So, if you get me in to your project to see what you’ve been modelling, and you have one of these diagrams over your desk, don’t expect me to be impressed.

About the Author Ian Mitchell

Ian Mitchell is a business analyst and software developer. He's been using UML since before it was UML, and has managed teams of BAs all over the place. He also teaches UML and BPMN, and writes the eaDocX document generator for the Sparx EA tool.

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