D. GRADUATE RATE
No	Converter name	Category	Value	Unit	
1	Dropout rate	Converter	0.2	Constant	
2	Actual study rate	Converter	As formulated	Constant	
3	Passing rate for 1 component	Converter	80%	Percent	
4	Passing rate for 2 components	Converter	As formulated	Percent	
5	Average training time	Converter	As formulated	Quarter	
6	Course duration	Converter	1	Quarter	
7	Students	Block	0	People	
8	Graduates	Block	0	People	
9	Lost students rate	Flow	As formulated	People/quarter	
10	Graduate rate	Flow	As formulated	People/quarter	

The Graduate rate is one of the important and difficult flows in this model. According to the nature of ITOA operation and in the concept of graduation, the student can only enrol on level of each course in ITOA. There are also 2 components in each level and after passing two components, the student can obtain the certificate for that level. Therefore, the logic from this scenario the author suggests here is that instead of differentiating the failed students in which component, we can calculate the number of students at any point of time with the average training time that students may have in order to complete the level. The passing rate for 1 component is 80%, and after completing successfully component 1, the student can continue to complete the component 2. Consequently, the rate that the student can pass all 2 components will be 80% multiplied by 80%, because the passing rate for 2 components is the same. 
Formulation: Passing_rate_for_2_components  = Passing_rate_for_1_component * Passing_rate_for_1_component
We also have the course duration, therefore, the average time that student can pass all components and obtain the corresponding certificate is:
Formulation: Average training time =  Course_duration/(Passing_rate_for_2_components)
There is another consideration here is the dropout rate determines how many students actually study in ITOA, which is one over five. Hence, after having actual student study in ITOA, we can have the graduate rate as below:
Formulation: Graduate rate = (Actual_study_rate*Students)/Average_training_time