Making Software

The Second Experiment: Comparing Pattern Solutions to Simpler Ones

The second experiment came about in an unexpected way. The company sd&m held a technical conference near Frankfurt, Germany some time in 1997. A number of speakers were invited, and I was among them. I talked about design patterns, our early results with pattern documentation, and how important it was to see whether design patterns really worked. I ended by saying that I was looking for subjects in a pattern experiment, and as a benefit for participating, I would offer an intensive pattern course, discussing all the major patterns known at the time. The president and founder of the company, Ernst Denert, sat in the front row. When I had finished he stood up, walked to the stage, and asked for my microphone. What was going to happen next? Taking away the speaker’s microphone is not exactly how the question-and-answer period after a talk works. He then turned to his employees (there were perhaps 150 in the room, most of them developers) and said: “You heard what Professor Tichy said. I don’t have anything to add to that. Who is going to participate?” After a few seconds of silence, a lot of hands went up! I’ve never had more effective encouragement for participation in any experiment, ever. After preparation and with the various scheduling conflicts, we actually ended up with 29 professional developers from sd&m participating. The experiment was conducted at sd&m’s Munich office in November 1997.

The experiment sought ...