Following a recent presentation, a debate started around the most expensive typo that people had encountered. My own contribution to the discussion was my experience of a design specification that had the words “a synchronous interface” to describe the messaging mechanism between two systems. The text passed though several reviews without comment and the system was built according to the design. When the customer tested the interface, he raised some observations that seemed peculiar initially, until we realised that he was after “an asynchronous interface” – a significantly more complex design in itself, notwithstanding the time lost in developing the incorrect solution. In the end, putting matters right cost the project a month’s schedule delay.
This sort of miscommunication can be avoided in a couple of ways. If using rigorous design documentation, have this contain two different types of model each complementing the other, such a diagram alongside a textual description. Even better, use collaborative working and have the parties explain the design to the other, ideally face to face, using different types of model. In this way, a misunderstanding in one model is uncovered by explaining the same thing in another.
This is all very well, but what about if you have to write some high-level requirement statements for a commercial contract? The answer is – be careful – lawyers don’t generally like anything but the simplest diagrams, so the modelling options are restricted. Some suggestions would be the following. Firstly, frame the text in terms of business outcomes rather than prescriptive statements. This allows the implementation team the flexibility to deliver in a manner of its choosing. Secondly, help your lawyers by being clear with your requirements wording – especially avoiding compound sentences – you don’t want to become responsible for a two-million-dollar comma.