Keeping the Vectors Short

"So," said Roscoe, "let's continue with our analysis. In our geometrical analogy, if time and resources are proportional to path length, we can see that Mr. Short Vector only needs 20 percent more than the minimum required for success, while Mr. Long Vector needs 50 percent more than the minimum. So Mr. Short Vector has much more margin for error.

"Another way to look at this is to measure scrap and rework. Out of the 12 units that Mr. Short Vector expends, 10 are required to get the result, and 2 are wasted, so his scrap and rework represents about 16 percent of the total effort. Mr. Long Vector wastes 5 out of 15 units expended, so his scrap and rework represents 33 percent of the total. Using scrap and rework as a metric, Mr. Long Vector is twice as bad as Mr. Short Vector." Roscoe was quite convincing.

"OK, Roscoe," I conceded. "It seems that short vectors are a good all-around principle in project management. But why is the concept even more important in software development projects?"

"I'll be glad to tell you, Sonny," said Roscoe triumphantly. "Why don't you get us some more coffee first?" Then he lit up one of his favorite stogies.^[4]

^[4] The Surgeon General wants me to remind you that smoking is bad for your health. Roscoe may live to be a hundred, but if you smoke, you shouldn't count on it. And, by the way, "stogie" has an interesting etymology. It comes from a town in Pennsylvania named Conestoga, where they made an inexpensive, slender, cylindrical cigar that was popular in the 1840s. It is also likely that drivers of Conestoga wagons (also manufactured in Conestoga!) smoked stogies. Roscoe's grandfather probably drove a Conestoga wagon, also known as a prairie schooner.