You’re driving home from work, and hear on the radio that there’s congestion on your usual route. It’s only fifteen miles, but it sounds like the trip would take at least an hour. You could take the highway instead–it’s three times as far, but at over 60 miles an hour you’d be home in less than 45 minutes.
Which route is more efficient?
This isn’t really an SAT question – it’s a management question and it illustrates the problem with questions of efficiency and similar fuzzy concepts of effectiveness. My car gets about 33 miles per gallon at highway speeds. In stop and go congestion, though, my car’s only getting 15 MPG. Which is more efficient? In terms of total gas use, the numbers are reversed. The usual route will only use a gallon while the alternate will require almost 50% more. On a “gallon’s per commute” basis it’s better to sit in traffic. Of course, there’s also the issue of efficient use of my time – what’s the value of 15 minutes driving saved?
This is the same problem faced when juggling the trade off between project cost (typically a function of people hours worked) and project (calendar) time. Project management metrics can illustrate the problem and the trade offs but in the end it’s a matter of differential valuation of requirements: a matter of values.
(As an aside, it’s interesting that hybrid systems like the Toyota Prius tackle efficiency at both ends. A very small gasoline engine provides even better highway mileage while the low horsepower but high torque electric engine prevents wasteful idling and low-RPM movement in stop and go traffic.)
