## 4 Results and Discussion
Although the mechanics selected for the MARISA Game did not prove to be wrong, due to time constraints dictated by operational duties of the persons participating to the experiments, it was agreed at the beginning of both experiment sessions to increase the number of knowledge cards provided to the player at each turn and to modify the winning condition. More specifically, it was agreed that the winner is the player collecting more knowledge tokens in a certain amount of time. Due to this change, the players were also invited to focus on the Islands corresponding to the illegal activity on which they had more expertise. This suggests that the game mechanics that support quick games should be preferred. As discussed in Section 3.3, there are two different types of knowledge card layouts. Most of the players stated that the graphical presentation of the knowledge structure is very useful if there are not many variables (\(D\)) in addition to the query variable. The average response was that the graphical presentation is convenient for \(D\leq 4\), while, for \(D>4\), the presentation in natural language form appears to be more adequate. However, those are preliminary observations and further investigation should be performed. From the verbal feedback and the feedback questionnaire, the MARISA Game appears to be perceived as a more engaging and stimulating method compared to traditional approaches to elicit the CPTs for Bayesian networks. Appendix A presents the self-reported results of the game PX assessment in the form of frequency tables. It includes also the response rate, the mode (\(Mo\)), and the interquartile range (\(IQR\)), which is adopted as an index of consensus (\(IQR=0\) for strong consensus). The results of the questionnaire show that the overall attitude towards the game is positive. The game was perceived as an adequate experimentation tool (\(Mo=4\), \(IQR=0.25\)). However, players did not have the initial feeling that it would be easy (initial feeling of ease \(Mo=3\), \(IQR=0.50\)), they felt confident that the experiment would support the stated goal, thanks to the facilitation approach (\(Mo=4\), \(IQR=1.00\)) and to the game structure and content (\(Mo=4\), \(IQR=0.25\)). However, it appears that it was not very clear for all the players _how_ the game relates to the stated goal (\(Mo=4\), \(IQR=2.00\)). This might be due to the fact that most of the players were not familiar with the MSDBN Service concepts or the MARISA project. Therefore, the introduction brief providing context to the participants should have been more detailed and focused on this aspect. The answers suggest that several players have a preference of using games over other KA methods. However, there is no consensus on this (\(Mo=5\), \(IQR=2.25\)). This might also be linked to the fact that none of them was involved in the KA session where traditional approaches were employed. The responses regarding flow show that the participants were concentrated (\(Mo=4\), \(IQR=0.25\)) and some fully occupied with the game (\(Mo=5\), \(IQR=2.00\)), but, as expected, the MARISA Game is not a high-engagement game that leads to a full immersion, forgetting about time (i.e., lost of track of time: \(Mo=1\), \(IQR=2.00\)) and surroundings (i.e., forgot about surroundings: \(Mo=1\), \(IQR=2.00\)). As can be observed in Appendix A, an overall positive feedback has been provided with respect to:  
1. the usability of the game as a system;
2. the facilitation process;
3. the sensory and imaginative immersion;
4. the players' satisfaction. However, responses report a moderate level of monotony of the game session (\(Mo=3\), \(IQR=1.25\)), of challenge (\(Mo=3\), \(IQR=1.25\)) and of impressiveness (\(Mo=3\), \(IQR=1.25\)). Moreover, it was not perceived by most players as a rich experience (\(Mo=2\), \(IQR=1.25\)). Therefore, future developments of this game should address these aspects. Finally, an interesting result was observed through the feedback related to workload.