Recently, however, usability's implications in the application core have been highlighted. Some authors have already illustrated, albeit informally, a possible relationship between usability and architectural design (Bass, 2003) (Folmer, 2004). If this relationship is confirmed, the cost of rework to achieve an acceptable level of usability would be much higher than expected according to the hypothesis of separation. If this is the case, usability should be dealt with earlier in the development process in order to define and evaluate its impact on design as soon as possible. Notice that this approach is consistent with the tendency in SE to carefully consider quality attributes early on in the development process (Barbacci, 2003). This strategy has already been applied to other quality attributes like performance, modifiability, reliability, availability and maintainability, where a number of authors have proposed techniques to deal with these attributes, for example, at architectural design time