Impact of unified user-story-based modeling on agile methods: aspects on requirements, design and life cycle management

User Stories (US) are the most commonly used requirements artifacts within agile methods such as XP and Scrum. They are written in the form of text of maximum two lines in natural language using prose or following a specific template. Traditionally, they are written down on an index card and posted on a wall or whiteboard for analyzing and monitoring the progress of the project. This performs well when the number of US is limited; but not so well when the number of US is large. In practice, many templates have been proposed with no semantic associated to each syntax used in the templates. This leads to series of issues looking alike different stakeholders interpreting the purpose of the US differently and results in making the whole set difficult to structure and analyze. In the end, this translates in misinterpretation of requirements.
This thesis starts with studying existing US templates in order to build a (consistent) unified model for their use with, for each keyword, a syntax and associated semantic. Particularly, this thesis studies US templates following the structure: As [WHO], I want [WHAT], so that [WHY]. Additionally, we also build a derived graphical representation for representing a US set to better analyze dependencies and alternatives of US. This notably allows building a view of the system-to-be on multiple aggregation level. A coarse-grained view can help the development team to better manage the life cycle of the application development by selecting relevant US to be developed within the coming iteration(s). Additionally, a fine-grained view allows dealing with the details of the functions to be developed.