The scientifically based Stage-Gate model is associated with Robert Cooper (1986), which divides the new product and service development process into five stages or five gates or decision points. The gates are actually quality assessment criteria, where the quality of the idea is evaluated according to the following questions:

 

At the end of each phase, the evaluation of development projects can lead to five possible outcomes: launch, termination, hold, recycling or conditional launch. From this perspective, decisions on the fate of individual development ideas are made with a degree of objectivity, which is particularly important in organisations where many development projects are running in parallel.

 

 

The steps in the five-stage process and the associated gates or evaluation criteria clearly illustrate the complexity of product and service development. The enhanced idea generation system is adaptive. It uses spiral or iterative development and aims to show something to customers and potential buyers as early and as often as possible through a series of build-test-modify cycles (Figure 21). According to large enterprise practice, new products are less than 50 per cent defined at the start of development and evolve and adapt to new information during development and testing. The process is also flexible in that the operations of each stage and the results associated with each gate are unique to each development project, based on the market context and the requirements of the development process. It is therefore advisable for each organisation to define its own criteria and only continue development once these have been met. In the case of small and medium-sized enterprises, where there is typically less parallel development and the owner or owner-manager is more emotionally involved, it is more difficult to make the tough decision to halt development. This is why it is necessary to build and manage a development portfolio using agile methods.

 

Build. In each iteration, build something you can show to the customer, such as a rough prototype, a protocept, a rough working model, or an early beta version.

Test. Test each version of the product with customers and let them tell you what they like and what value they see in it.

Feedback. Gather feedback from potential customers or users on each version of the product.

Modification. Rethink the value proposition based on the feedback, including the expected benefits and the design characteristics and features of the product, and then start the cycle over.

 

Each cycle brings the project closer to the final product design. This spiral approach encourages experimentation and encourages project teams to make mistakes often, quickly and cheaply, a principle that Jobs applied throughout his development career at Apple. Spiral development is also consistent with two key principles of the Agile Manifesto for software development:1 responding quickly to change and continuously involving customers or stakeholders in product development.