Alistair Cockburn - Agile Software Development

Games fall into many categories: zero-sum, nonzero-sum, positional, competitive, cooperative, finite, and infinite, to name a few (see Figure 1-1). As a way to help identify what kind of game software development could be, let's look at those choices.

Figure 1-1. Different categories of games.

Zero-sum games are those with two sides playing in opposition, so that if one side wins, the other loses. Checkers, tic-tac-toe, bridge, and tennis are examples. Software development is clearly not a zero-sum game.

Non-zero-sum games are those with multiple winners or multiple losers. Many of the games you would consider playing on that winter's evening are non-zero-sum games: poker, pachisi, and hide-and-seek. Software development is also a non-zero-sum game.

Positional games are those in which the entire state of the game can be discovered by looking at the markers on the board at that moment. Chess and tic-tac-toe are examples. Bridge isn't, because the played cards don't show which person played them.

Some people try to play software development as a positional game, requiring that the documentation reflect the history and current state of the project. They intend that, should anyone leave the project, a replacement person will be able to join, read the documentation, and pick up where the other person left off. We shall come to see that this is not an effective gaming strategy for software development.

(Positional games are actually far more interesting than the simple description above implies. John Conway, in his book On Numbers and Games, was able to show how two-person, positional games form a superset of all numbers: real, imaginary, finite, and transfinite. He constructs the notion of number directly from two-person, positional games.)

All the above are competitive games, in which there is a clear notion of winning and losing.

In cooperative games, the people work either to win together or to continue the game as long as they consider it worth playing. The former are goal-seeking cooperative games, the latter non-goal-seeking cooperative games. Story telling, playing jazz, and carpet wrestling are non-goal-seeking cooperative games. In these latter games, the players do not seek to end the game by reaching a goal as fast as possible. They come to an end only when enough people get tired of playing and step out.

Charades, rock climbing and software development are goal-seeking cooperative games (see Figure 1-1 again).

All of the above are finite games, games intended to end. Infinite games are those in which the players' primary intention is to keep the game going. Organizations, corporations, and countries play these. Their core purpose is to stay in existence.

A person's profession is also an infinite game. The person, wanting to continue the profession, makes a set of moves that permit his practice of that profession to continue.

Often, a person or company aims to play well on a particular project in order to get the best position on the next game. As with the card game appropriately named "So long, sucker," these sorts of teams and alliances change continually and without notice.

Software and Rock Climbing

Of all the comparison partners for software development that I have seen, rock climbing has emerged as the best. It is useful to have such a comparison partner, to get some distance from the subject, and open a vocabulary that we can reapply to software development. Rock climbing is not a metaphor for software development but a comparison partner, another member of the same class of games.

Let's see how some of the words and phrases associated with rock climbing relate to software development.

Cooperative and goal-seeking. A team of rock climbers work together to reach the top. They will evaluate the climb based on how well they climbed together and how much they enjoyed themselves, but the first measure of success is whether they reached the top. Reaching the endpoint is a primary goal, and the game is over when they reach the top.

(If you are a rock climber, you might well interrupt me here. For many rock climbers, the moment of reaching the end of the climb is a sad one, for it signals the end of the game. That is true of cooperative games in general. The game comes to an end when the endpoint is reached, but if the players have been enjoying themselves, they may not want to stop. Similarly, sometimes software developers do not want to finish their design, because then the fun part of their work will be over.)

Load bearing. The climbers must actually support their weight on their hands and feet. This is a particularly valuable point of comparison between the two: Software must run and produce reasonable responses. While multiple solutions are possible, not just any solution will do.

Team. Climbing is usually done in teams. There are solo climbers, but under normal circumstances, climbers form a team for the purpose of a climb.

Individuals with talent. Some people just naturally climb better than others do. Some people will never handle certain climbs.

Skill-sensitive. The rock climber must have certain proficiency. The novice can only approach simple climbs. With practice, the climber can attack more and more difficult climbs.

Training. Rock climbers are continually training on techniques to use.

Tools. Tools are a requirement for serious rock-climbing: chalk, chucks, harness, rope, carabiner, and so on. It is important to be able to reach for the right tool at the right moment. It is possible to climb very small distances with no tools. The longer the climb, however, the more critical the tool selection is.

Resource-limited. A climb usually needs to be completed by nightfall or before the weather changes. Climbers plan their climbs to fit their time and energy budget.

Plan. Whether bouldering, doing a single-rope climb, or doing a multi-day climb, the climbers always make a plan. The longer the climb, the more extensive the plan must be, even though the team knows that the plan will be insufficient and even wrong in places.

Improvised. Unforeseen, unforeseeable, and purely chance obstacles are certain to show up on even the most meticulously planned climbing expeditions unless the climb is short and the people have already done it several times before. Therefore, the climbers must be prepared to change their plans, to improvise, at a moment's notice.

Fun. Climbers climb because it is fun. Climbers experience a sense of flow (Csikszentmihalyi 1991) while climbing, and this total occupation is part of what makes it fun. Similarly, programmers typically enjoy their work, and part of that enjoyment is getting into the flow of designing or programming. Flow in the case of rock climbing is both physical and mental. Flow in the case of programming is purely mental.

Challenging. Climbers climb because there is a challenge: Can they really make it to the top? Programmers often crave this challenge, too. If programmers do not find their assignment challenging, they may quit or start embellishing the system with design elements they find challenging (rather like some of the poets mentioned in the epic poetry project).

Dangerous. Probably the one aspect of rock climbing that does not transfer to software development is danger. If you take a bad fall, you can die. Rock climbers are fond of saying that climbing with proper care is less dangerous than driving a car. However, I have not heard programmers express the need to compare the danger of programming with the danger of driving a car.

Software development has been compared with many other things, including math, science, engineering, theatre, bridge building, and law. Although one can gain some insight from looking at any of those activities, the rock-climbing comparison is the most useful for the purpose of understanding the factors involved in the activity.