1) They do not have a definitive formulation.
2) They do not have a “stopping rule.” In other words, these problems lack an inherent logic that signals when they are solved.
3) Their solutions are not true or false, only good or bad.
4) There is no way to test the solution to a wicked problem.
5) They cannot be studied through trial and error. Their solutions are irreversible so, as Rittel and Webber put it, “every trial counts.”
6) There is no end to the number of solutions or approaches to a wicked problem.
7) All wicked problems are essentially unique.
8) Wicked problems can always be described as the symptom of other problems.
9) The way a wicked problem is described determines its possible solutions.
10) Planners, that is those who present solutions to these problems, have no right to be wrong. Unlike mathematicians, “planners are liable for the consequences of the solutions they generate; the effects can matter a great deal to the people who are touched by those actions.”
