The Bison Valley Ax Works had just implemented a phased development process. Mr. Big, the general manager, was proud to bring order to his chaotic engineers. The development process was neatly divided into planning, concept design, detail design, prototyping, design verification, and pre-production. Each phase had specific activities logically assigned with clear entry and exit criteria. Now, the pure light of logic and reason would burn brightly in the Bison Valley Ax Works.
Just in case this light didn't reach the darker corners of the engineering department, Mr. Big made sure that they were illuminated with a special day of intense training. Every engineer was forced in unison to read the new procedure aloud. Now, nobody could use the lame old engineering excuse, "Gee, nobody ever told me that we were supposed to do that."
Fresh from his training, Ogg, the Cro-Magnon design engineer, walked into the prototype shop. His new ax design, the Mammoth Whacker III, was in the concept design phase. He wanted to change the length of the handle to see if that would increase throwing distance.
"Hey, Grnk," he said to the technician in the prototype shop. "Can you take about an inch off this handle?"
"No can do," responded Grnk.
"Of course you can. It's soft wood and easy to work with," Ogg said.
"That's not what I mean," said Grnk. "Check the sign on the door. This is the prototype shop. We do prototypes. Your project is still in concept design."
Ogg looked baffled. "But I need a prototype to test the concept and I need to test the concept before I do detailed design. I can't, however, get a prototype until I complete detailed design."
"Exactly. So what's your point?" Grnk asked.
"Don't you see?" Ogg exclaimed. "It's a logical impossibility."
"Listen Ogg," Grnk coolly stated. "I'm just a simple technician. Don't try to fool me with your fancy engineering talk. All I know is that prototypes are done in the prototype phase, and you're not in that phase."
Ogg stopped and thought. There must be some way out of this dilemma. Surely, his large Cro-Magnon brain could find a solution. "Say, Grnk, could you build me a concept feasibility model?" he ventured.
"What's that?" Grnk inquired.
"Oh, it's just an engineering term for the first physical instantiation of a design," Ogg said.
"Are you sure it isn't a prototype?" questioned Grnk, doubtfully.
"Of course not," Ogg replied. "We only do prototypes in the prototype phase."
In most phased development, the great danger is the concept of gates. If we can't be on both sides of a gate at the same time, then we can only be in one phase at a time. This makes phases sequential, invariably slowing product development. A better alternative is permitting out-of-phase activity when it can be economically justified. Most engineers will engage in these out-of-phase activities anyway, because they have a naive inclination to do what makes sense. The choice lies between making such behavior visible, or driving it underground. If it's visible, one can manage it. But if it's not, engineers will develop brilliantly creative ways to convince you that a prototype is not a prototype. As a wise senior executive told me recently, "We have 20 different words for prototype and none of them begin with the letter p."