Difficulty of engagement is a notion in the Campbell paradigm, a model of behavior change with person-independent difficulty.
Most of these models rely on people's perceptions and estimates of behavioral difficulty.
A more objective measure of difficulty is desirable, e.g., for environmental or energy policy, because people may misperceive the difficulty of behaviors, possibly because affected by mood or current circumstances.
[2] The Campbell paradigm was proposed by Kaiser et al.[3] as a model of behavior change with person-independent difficulty.
The more demanding these barriers[clarification needed] are, the more favorable attitude towards a general goal, such as environment protection.