Horst Rittel and Melvin Webber developed the concept of wicked problems in relation to planning issues. I've done work with planners and have experienced their frequent 'yes, but' responses during Idea Generation phases of creative problem solving, so I recognise that their field is constrained by many competing factors. Rittel and Webber identified the challenge of context in dealing with social problems, which makes these wicked problems so difficult to tackle.
Rittel and Webber identified at least 10 distinguishing properties of wicked problems summarised in the following extract from their 1973 paper:
1 There is no definitive formulation of a wicked problem
The information needed to understand the problem depends upon one's idea for solving it. In order to describe a wicked problem in sufficient detail, one has to develop an exhaustive inventory of all conceivable solutions ahead of time. The reason is that every question asking for additional information depends upon the understanding of the problem - and its resolution - at that time.
2 Wicked problems have no stopping rule
In solving a chess problem or a mathematical equation, the problem-solver knows when he has done his job. There are criteria that tell when the or a solution has been found.
Not so with planning problems.
The planner terminates work on a wicked problem, not for reasons inherent in the "logic" of the problem. He stops for considerations external to the problem: he runs out of time, or money, or patience.
3 Solutions to wicked problems are not true-or-false, but good-or-bad
There are conventionalised criteria for objectively deciding whether the offered solution to an equation or proposed formula of a chemical compound is correct or false.
For wicked problems, there are no true or false answers. Normally, many parties are equally equipped, interested, and/or entitled to judge the solutions, although none has the power to set formal decision rules to determine correctness. Their judgments are likely to differ widely to accord with their group or personal interests, their special value-sets, and their ideological predilections. Their assessments of proposed solutions are expressed as "good" or "bad" or, more likely, as "better or worse" or "satisfying" or "good enough".
4 There is no immediate and no ultimate test of a solution to a wicked problem
For tame-problems one can determine on the spot how good a solution-attempt has been.
With wicked problems, 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. In such cases, one would have been better off if the plan had never been carried out.
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
In the sciences and in fields like mathematics, chess, puzzle solving or mechanical engineering design, the problem solver can try various runs without penalty. A lost chess game is seldom consequential for other chess games or for non-chess-players.
With wicked planning problems, however, every implemented solution is consequential. It leaves "traces" that cannot be undone. One cannot build a freeway to see how it works, and then easily correct it after unsatisfactory performance. Large public-works are effectively irreversible, and the consequences they generate have long half-lives.
Whenever actions are effectively irreversible and whenever the half lives of the consequences are long, every trial counts. And every attempt to reverse a decisions or to correct for the undesired consequences poses another set of wicked problems, which are in turn subject to the same dilemmas.'
[Town planners in Glasgow wanted to solve the problems of slums by building a brave new world of tower blocks called the Gorbals. The break up of communities contributed to stress and isolation. 38 years later the last 2 tower blocks were demolished in 2008]
'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 solutions to a wicked problem have been identified and considered.
Normally, in the pursuit of a wicked planning problem, a host of potential solutions arises; and another host is never thought up. And it is, of course, a matter of judgment which of these solutions should be pursued and implemented.
Chess has a finite set of rules, accounting for all situations that can occur. In mathematics, the tool chest of operations is also explicit; so, too, although less rigourously, in chemistry.
7 Every wicked problem is essentially unique
Despite seeming similarities among wicked problems, one can never be certain that the particulars of a problem do not override its commonalities with other problems already dealt with.
The conditions in a city constructing a subway may look similar to conditions in San Francisco, say; but planners would be ill-advised to transfer the San Francisco solutions directly.
8 Every wicked problem can be considered to be a symptom of another problem
Problems can be described as discrepancies between the state of affairs as it is and the state as it ought to be. The process of resolving the problem starts with the search for causal explanation of the discrepancy. Removal of that cause poses another problem of which the original problem is a "symptom". In turn, it can be considered the symptom of still another, "higher level" problem. Thus "crime in the streets" can be considered as a symptom of general moral decay, or permissiveness, or deficient opportunity, or wealth, or poverty, or whatever causal explanation you happen to like best. The level at which a problem is settled depends upon the self-confidence of the analyst and cannot be decided on logical grounds. There is nothing like a natrual level of a wicked problem.
9 The existence of a discrepancy representing a wicked problem can be explained in numerous ways. The choice of explanation determines the nature of the problem's resolution
"Crime in the streets" can be explained by not enough police, by too many criminals, by inadequate laws, too many police, cultural deprivation, deficient opportunity, too many guns, phrenologic aberrations etc. Each of these offers a direction for attacking crime in the streets. Which one is right? There is no rule or procedure to determine the "correct" explanation or combination of them. The reason is that in dealing with wicked problems there are several more ways of refuting a hypothesis than there are permissible in the sciences.
The choice of explanation is arbitrary in the logical sense. In actuality, attitudinal criteria guide the choice. People choose those explanations which are most plausbile to them.
10 The planner has no right to be wrong
As Karl Popper argues, it is a principle of science that solutions to problems are only hypotheses offered for refutation. This habit is based on the insight that there are no proofs to hypotheses, only potential refutations. The more a hypothesis withstands numerous attempts at refutation, the better its "corroboration" is considered to be. Consequently, the scientific community does not blame its members for postulation hypotheses that are later refuted.
In the world of planning and wicked problems no such immunity is tolerated. Here the aim is not to find the truth, but to improve some characteristics of the world where people live. Planners are liable for the consequences of the actions they generate; the effects can matter a great deal to those people that are touched by those actions.'
[In this case, from Arizona, the engineer gets the blame.]