The stock of “Hours Worked Per Day” has an inflow of “increase in hours,” determined by the number of “Hours Worked Per Day” and a constant “INCREASE FRACTION” (0.1) The “increase in hours” positive feedback loop shows that the more peron works on the project, the more he likes it, causing him to work even more.
The number of “Hours Worked Per Day” decreases through a “decrease in hours”,” which is the product of the “Hours Worked Per Day” and a “decrease fraction.” The “decrease fraction” depends on a “NORMAL DECREASE FRACTION”(0.05) and an “effect of health on decrease fraction” multiplier. The multiplier reflects a negative relationship between “Health” and the “decrease fraction”: as the ratio of “Health” to “INITIAL HEALTH” decreases, the “decrease fraction” increases.
Till “Health” is still relatively strong, the “effect of health on decrease fraction” will be quite small.
Since “Hours Worked Per Day” increases from 8 to 16 hours on the 18 day “Helth” decreases from 100 to 69, wich is less than accepted 75.
Such a high value for the multiplier emphasizes the fact that person would startcutting back on his hours quite drastically if he started to become seriously ill.
Based on materials, prepared for the
MIT System Dynamics in Education Project
Under the Supervision of
Prof. Jay W. Forrester
High Tech CEO, Pennsylvania