Cooper’s Stage-Gate Process Model

Cooper’s stage gate
model is a variant of the waterfall. It splits the life-cycle into six stages separated by “gates.” Each gate is a decision point. It differs from the waterfall in that the activities in each stage may
be simultaneous [Cooper]

•Discovery stage: a product manager thinks of a new idea for a product.
– Idea screen: the idea is presented to potential stakeholders for their buy-in.
•Scoping stage: the market for the product is assessed and key features are identified.
– Second screen: the idea is re-presented to potential stakeholders for their buy-in, but with more-rigorous requirements and other information.
•The business case stage: in which the product, market, organization, project management and environment, competitors, budget, RoI, and legal issues are defined.
– Go to development is the moment at which the organization can commit to the large budget required for development.
•The development stage includes requirements refining, design, code, and build. Its output is a product ready for beta testing.
–Go to testing is the moment when the testing budget and the marketing and operational plans must be committed to. It is based on the continued existence of a market opportunity.
•Testing is system and acceptance testing at internal and friendly customer sites. It generates a
product fit for launch.
–Go to launch: is the moment when marketing and training plans become operative.
•Launch the product.

It is easy to see a number of critical dangers in this approach:
• Half the activities are oriented to the development of a business case. Since this is likely to occupy between 5–10% of the total manpower, more detail on the other 90–95% of the manpower’s activities would be useful.
• No allowance has been made for the (inevitable) requirements changes.
• Testing is relegated to the penultimate activity. The possibility that the requirements are deeply flawed will thus tend to be hidden. Similarly the testers will not learn how to use the product until too late causing considerable delay. The tests they prepare may thus need much rewriting.
• That a decision can be taken on the marketability of a product which has yet to enter beta testing requires enormous faith in the ability of developers. The amount of iteration between the development and testing groups is not shown, and the delays (which will also affect the go-to-market decision) can be considerable.

To make such a process work it is imperative that testers:
• Focus on the earliest access to the requirements as they are assembled.
• Get early access to prototype versions so they can prepare tests.
• Provide review and possibly modeling feedback to management such that inconsistent or missing requirements be identified asap.