Product Line Engineering (PLE) is an effective reuse methodology where common features among members are captured into core assets and applications are produced by reusing the core assets, reducing development cost while increasing productivity. To maximize the reusability of core assets, optimal scoping of core assets is essential. If the scope is excessively broad, it will result in high cost of asset development while lowering reusability. On the other hand, if the scope is too narrow, it will result in a limited applicability, only supporting a small number of members in the domain.

In this paper, we propose a process for domain analysis and economical analysis of core asset scope. Then, we define guidelines for each activity of the process. Since variability often occurs in PLE, we significantly treat the variability of features among members. By applying our scoping framework, one can develop core assets of which scope provide the most economical value.