  The use of digital resources has been increasing in every instance of todays
society, being it in business or even ludic purposes. Despite such ever
increasing use of technologies as interfaces, in all fields, it seems that it
lacks the importance of users perception in this context. This work aims to
present a case study about the evaluation of ECAs. We propose a Long-Term
Interaction (LTI) to evaluate our conversational agent effectiveness through
the user perception and compare it with Short-Term Interactions (STIs),
performed by three users. Results show that many different aspects of users
perception about the chosen ECA (i.e. Arthur) could be evaluated in our case
study, in particular that LTI and STI are both important in order to have a
better understanding of ECA impact in UX.
