The Mentor Project Model: A Model for Experimental Development of Contract Software

The Mentor project model supports experimental development of contract software. The application area is interactive information systems, i.e. systems closely integrated with user work practice: The Mentor project model is a spiral model with iteration of activities such as (re-)design, estimation and negotiation, development and evaluation of prototypes. End-users are actively involved in design and evaluation. Repeated estimation and negotiation activities based on a calculation model for estimating system extent ensure that growth in extent is made visible and is subject to explicit decisions balancing use quality of the system with cost and schedule. The project model defines how to share the cost of experimentation between customer and supplier. The project model is in current use and has been successfully used in several large projects during the last 6 years. This paper contains a synthesis of the practical experiences gained through these projects and relates the project model to ongoing discussions of system development methodologies. The model contributes to the discussions by focusing on contract software and by giving elaborate suggestions for how to prototype large information systems with many users.