Pick a Number... Any Number?

A recent classroom revelation caused us to reconsider the adequacy of the instructions offered in our textbooks for one of our most elementary quantitative methods. Specifically, we found that many students were mystified concerning how to pick an initial objective function value when plotting an isoprofit line in order to graphically solve a linear programming problem. We observed that this seemingly insignificant issue was causing a surprising amount of wasted time, confusion, and even anxiety. Our experience indicated that students do not necessarily possess any consistent intuition for choosing an appropriate initial value. We confirmed this perception through informal experimentation. We reviewed several textbooks and found that most simply do not bother to address this issue. Therefore, we devised a simple, comprehensible method which we have taught our students to resolve or avoid this problem. Although we quickly found the method to be helpful for many students, we conducted an experiment to formally measure its effect.