## 3 The Early Phase Project Scope Estimation Methodology
### Compiling Requirements List
#### 3.2.2 Reconciliation of Requirements  
After the initial transformation, reconciliation of requirements is the next step in achieving consensus on scope. Reconciliation of requirements consists of two steps:  
- Unification of domain concepts (step S3 in Figure 2);  
- Identification of overlapping requirements (Step S4 in Figure 2);  
In various models prepared by different participants of requirements workshop, the same elements of domain can be named differently (e.g., user, person, and client can be used to denote the same role; furthermore, abbreviations can also be used). The unification of the domain concepts encompasses the identification of synonyms of nouns and verbs and mapping them, by deciding which one of the synonyms should be used and replacing all other synonyms with the chosen one. Identifying synonyms ensures that the terms that are used in the project are understood in the same way by everyone. The initial identification of synonyms can be performed straightforwardly according to the English dictionary, but the final mapping decisions should be made by a subject matter expert. Noun mapping is more straightforward than that of verbs, as while replacing verbs, one must ensure that they do not change the context, and each replacement must be reviewed. Thus, verb alignment takes longer and may yield less value. However, understanding the verbs used and related terminology is essential. Another important aspect is identification of similar Contexts and aggregation of these Contexts to ensure better grouping of requirements for the next step. In general, unifying the domain concepts is important not only in reconciling the requirements, but also in the formation of user wireframes and high-fidelity frames, as the same vocabulary is used. Maintaining consistency and compliance with organizational terms is one of the most important criteria for a good user experience. The higher the number of participants in modeling requirements, the more likely it is that there will be more changes required due to synonyms used. At the same time, it ensures that the management of overlapping requirements will be more effective. Overlapping requirements often lead to duplication of effort or resources, inconsistencies, and conflicts during the project, and risks of major scope changes. Therefore, it is important to identify overlaps as early as possible in the project for ensuring consistency and quality of the requirements, clarifying the scope, and thus facilitating time efficiency, cost reduction, resource optimization, and stakeholder satisfaction. Managing of overlapping requirements consists of these steps:  
- Determining the primary source (model of textual input);Grouping elements (optional) and identifying overlapping requirements. Determining the primary model identifies which model the team considers to be the central or the most informative model. If it is difficult to identify, it can be determined by detecting which model outclasses others (i.e., was the source of the biggest number of generated requirements, and these requirements had the fewest replacements during unification of domain concepts). The next step is the grouping of requirements, which facilitates reducing the set of requirements in which we search for overlaps. For grouping, two parts of requirement can be used: Actor and Context. Context grouping helps to limit the set of requirements for identifying overlaps by area of functionality, as there is no need to compare requirements that describe different areas (e.g., registration or order creation). Actor grouping facilitates limiting the set of requirements in terms of roles responsible for the certain requirements, as it is easier to identify the overlapping functionality specified for the same role. Both Actor and Context grouping strategies are useful, but we suggest applying each of them consecutively to gain the maximum benefits and ensure thorough identification of overlaps.