Step 4-1 (set a threshold value to draw the IRM). In the above, the IRM is constructed based on the information from the matrix T to explain the structure relations of factors. But, in some situations, the IRM will be too complex to show the valuable information for decision making if all the relations are considered. Therefore, a threshold value θ is set in many studies to filter out negligible effects. That is, only the element of matrix T , whose influence level is greater than the value of θ , is selected and converted into an IRM.