IT Success!: Towards a New Model for Information Technology

1.4. The construction industry trap

Drawing on the construction industry, the IT department would develop systems for the rest of the business through a standard client-vendor relationship, based on a contractually signed-off requirements specifications document. This would then drive a sequential 'waterfall' method, with its strict linear approach from analysis, design, development and testing through to implementation, with each phase performed by different teams of specialists.

This proved to be a non-starter, and generally remains so to this day. You can specify requirements for a house because the desired outcome is relatively easy to conceive and visualize. You can then have it built 'to spec' by a vendor because the corresponding specifications (weights, dimensions and forces) cover standard mechanical components (beams, widgets, tiles) and are applied to the hard sciences (physics, engineering and mathematics) to produce relatively predictable results. In the construction industry, you can therefore separate the design phase (which constitutes on average less than 20% of the total effort) from the construction phase (which accounts for at least 80%) and have them done by different teams. You are also spared the burden of testing – after all, once you've calculated the maximum allowable stress for a beam based on the force of gravity and the strength of the materials you are using, then you can rest assured that it's not going to collapse.

Human behaviour however, which ...