waterfallThe Agile Manifesto is a story about software development, but its philosophy holds lessons that can apply to medical device design.

The Agile Manifesto grew out of frustration with the “waterfall” model of development:

1) Establish requirements

2) Design

3) Implement

4) Verify

5) Maintain

Reliance on this model resulted in a lot of attention being paid to the process but not much to the customer and what the customer was looking for. The Agile Manifesto sought to change not so much the process, but rather beliefs and values of the designers engaged in it. Specifically:

  • Individuals and interactions are valued over processes and tools.
  • Working software is valued over comprehensive documentation.
  • Customer collaboration is valued over contract negotiation.
  • Responding to change is valued over following a plan.

Medical device design has its own waterfall model:

1) User needs

2) Design input

3) Design process

4) Design output

5) Verification

6) Validation

Now, the FDA requires that this model be followed – it is the basis for Design Control. Its advantage over the original software development model is that it accounts for user needs up front, as the most important aspect. Where medical device design can learn from the Agile Manifesto however, is in its emphasis on fast iteration: responding to change is valued over following a plan. There is still a plan, but it comes together incrementally. In developing a complex medical device, not everything is known at the start. Changes will inevitably be required, and course adjustments will need to be made as learnings develop. Agile development recognizes this and makes it core to the process.