# Reasoning about Confidence in Goal Satisfaction
## 6 Case Study
### Confidence Propagation Interpretation  
The results of the nine GRL evaluation strategies were presented and discussed with the hospital representatives. Generally, the _current method_ alternative is better than the RTTS alternative mainly because of the cost. The hospital receives around 98,550 urgent cases and 558,450 routine cases yearly, which increases the cost of using an RTTS system dramatically. For critical situations, where they receive 49,275 cases yearly, and the cost seems to be affordable. The confidence in \"Have a low cost\" is very low (25) meaning that there is no obvious clue whether the actual cost would be more or less than the estimated cost used in the evaluation. As a result, the hospital investigated the cost of similar existing systems that were deployed in other contexts of other hospitals where the cost was higher than the estimated cost of RTTS, which is not affordable giving their current budget. At this point, it is essential for the hospital to monitor and evaluate the performance in the critical cases; hence the RTTS is a good option for them, and this is supported by the analysis of the goal model for that context. However, it is still expensive to have the system for the other two cases (urgent and routine). The confidence value of the cost is estimates (20), which diminishes the soundness of the satisfaction value of the cost and highlights the lack of reliability of the collected data.  
The evaluation of the goal model is not only about the cost; more importantly, it is about finding a solution to monitor the process of collecting samples in real time until results are delivered. The confidence in the satisfaction value of this goal, which is 75 using  
Figure 13: GRL model evaluation corresponding to the _RTTS by nurse_ alternative in a critical situation.  
the RTTS, is quite high. In addition, there is high confidence in the satisfaction of other goals such as to increase process efficiency and reduce turn around time. In terms of the performance goals, the confidence levels fall between 75 and 100 when using an RTTS.  
Another revealing aspect of the case study is that the hospital needs a real-time tracking system to track lab samples and other things; however, because the RTTS system was developed by a single programmer, not an official vendor, the hospital would not pay much for it at the moment. In addition, for the same reason, the _RTTS by Nurse_ alternative was more welcomed than the _Automated RTTS_ because the hospital would not risk typical security and privacy issues when exposing a wide range of patients medical records to the RTTS; nevertheless, the ER actor was less satisfied in the _RTTS by Nurse_ alternative compared to the _Automated RTTS_ alternative.  
The results of the evaluation of the alternatives for urgent and routine situations are similar to those for critical ones. The main difference rests in the cost involved, as discussed above. The hospital representative delivered the analysis results to administration leaders, supporting the suitability of using the RTTS as a temporary solution to fulfill identified needs for critical situations, while remaining affordable. Moreover, they will keep the current method for other situations (with higher loads) until they find a trusted vendor. The propagated confidence supported the idea of having a tracking system in order to satisfy almost all stakeholder goals in the short term and fulfill their immediate needs. However, for the long term, the confidence levels also show that some goals related to costs and to reducing the number of interactions with patients need to be fully addressed with more reliable data/evidence before adopting any solution.