ed as a funnel with a large number of new product ideas entering the concept stage, narrowing down to a fewer number in subsequent stages. Separating these each stage is a phase review where a decision is made to skip the product, enter into the next stage or redirect back to a previous stage for additional work. The purpose of the concept stage is to quickly assess a new product opportunities. This activity will be performed by a product manager with support from others in the team. The product concept proposal will typically include: description of product concept and unique/new selling proposition, Preliminary market opportunity assessment, economical overview, technical valuation, preliminary financial analysis, planned schedules, recommended core team members. The objective of the system level design is to define the product which has to be developed, and to complete the business strategy for the product. During the next stage the assumptions made during the concept stage are verified through further market research and competitive analysis. Engineering assumptions will be verified in this stage by more detailed design and feasibility tests.

Figure 2 Product development process
Source: https://sbpbusiness2000.wordpress.com/2013/01/25/new-product-development/
Lean Startup product development encourages us to first investigate if there is a need of the product in the market before we worry about the details of the new product. While old-style approaches also recommend carrying out market research and study before we engage in product planning and definition, lean approaches increase the speed at which a startup team will operate. This allows startup teams to fail and learn faster, to adapt their product strategy and tactics rapidly, and to hopefully launch the right product with the right features in the market.