I wonder if any of you can help a novice like me. It is my understanding that the contribution tree will show the percentage contributions of impacts for all the processes. Am I right in assuming that it should always add up to 100%? If you add up all the processes it seems to sum up to 93.93 % only. What happened to the 6.07%?
Below you can see the contribution tree (Figure 1) and the model graph of my product system (Figure 2). Can someone shed light on this matter?
Figure 1. Contribution tree
Figure 2. Model Graph
I will appreciate any help you can give me.