Rittel and Webber characterise wicked problems by the following 10 criteria. (It has been pointed out that some of these criteria are closely related or have a high degree of overlap, and that they should therefore be condensed into four or five more general criteria. I think that this is a mistake, and that we should treat these criteria as arising from 10 more or less specifically encountered “frustrations” the authors have experienced in dealing with complex social planning issues.)

1. There is no definite formulation of a wicked problem.
    “The information needed to understand the problem depends upon one’s idea for solving it. This is to say: in order to describe a wicked problem in sufficient detail, one has to develop an exhaustive inventory for all the conceivable solutions ahead of time.” [This seemingly incredible criterion is in fact treatable. See below.]

2. Wicked problems have no stopping rules.
    In solving a tame problem, “… the problem-solver knows when he has done his job. There are criteria that tell when the solution or a solution has been found”. With wicked problems you never come to a “final”, “complete” or “fully correct” solution – since you have no objective criteria for such. The problem is continually evolving and mutating. You stop when you run out of resources, when a result is subjectively deemed “good enough” or when we feel “we’ve done what we can…”

3. Solutions to wicked problems are not true-or-false, but better or worse.
    The criteria for judging the validity of a “solution” to a wicked problem are strongly stakeholder dependent. However, the judgments of different stakeholders …”are likely to differ widely to accord with their group or personal interests, their special value-sets, and their ideological predilections.” Different stakeholders see different “solutions” as simply better or worse.

4. There is no immediate and no ultimate test of a solution to a wicked problem.
    “… any solution, after being implemented, will generate waves of consequences over an extended – virtually an unbounded – period of time. Moreover, the next day’s consequences of the solution may yield utterly undesirable repercussions which outweigh the intended advantages or the advantages accomplished hitherto.”

5. Every solution to a wicked problem is a “one-shot operation”; because there is no opportunity to learn by trial-and-error, every attempt counts significantly.
    “… every implemented solution is consequential. It leaves “traces” that cannot be undone … And every attempt to reverse a decision or correct for the undesired consequences poses yet another set of wicked problems … .”

6. Wicked problems do not have an enumerable (or an exhaustively describable) set of potential solutions, nor is there a well-described set of permissible operations that may be incorporated into the plan.
    “There are no criteria which enable one to prove that all the solutions to a wicked problem have been identified and considered. It may happen that no solution is found, owing to logical inconsistencies in the ‘picture’ of the problem.”

7. Every wicked problem is essentially unique.
    “There are no classes of wicked problems in the sense that the principles of solution can be developed to fit all members of that class.” …Also, …”Part of the art of dealing with wicked problems is the art of not knowing too early which type of solution to apply.” [Note: this is very important point. See below.]

8. Every wicked problem can be considered to be a symptom of another [wicked] problem.
    Also, many internal aspects of a wicked problem can be considered to be symptoms of other internal aspects of the same problem. A good deal of mutual and circular causality is involved, and the problem has many causal levels to consider. Complex judgements are required in order to determine an appropriate level of abstraction needed to define the problem.

9. The causes of a wicked problem can be explained in numerous ways. The choice of explanation determines the nature of the problem’s resolution.
    “There is no rule or procedure to determine the ‘correct’ explanation or combination of [explanations for a wicked problem]. The reason is that in dealing with wicked problems there are several more ways of refuting a hypothesis than there are permissible in the [e.g. physical] sciences.”
10. [With wicked problems,] the planner has no right to be wrong.
    In “hard” science, the researcher is allowed to make hypotheses that are later refuted. Indeed, it is just such hypothesis generation that is a primary motive force behind scientific development (Ritchey, 1991). Thus one is not penalised for making hypothesis that turn out to be wrong. “In the world of … wicked problems no such immunity is tolerated. Here the aim is not to find the truth, but to improve some characteristic of the world where people live. Planners are liable for the consequences of the actions they generate …”

Project coordinator: Richard Tanter
17 May 2008