Difficulty is critical: The importance of social factors in modeling diffusion of green products and practices

Despite the very positive -- as measured by market surveys -- attitude towards eco-innovations and sustainability in general, the actual market penetration of green products and practices generally falls behind the expectations. In this paper we argue that considering \emph{difficulty of engagement}, as used in the Campbell Paradigm, is of critical importance when modeling diffusion of eco-innovations. Such a notion of difficulty possesses three desired properties: (i) parsimony -- it is represented by a single value, (ii) interpretability -- it can be regarded as an estimator of the otherwise complex notion of \emph{behavioral cost}, and (iii) applicability -- it can be easily measured through market surveys. In an extensive simulation and analytical study involving empirically measured difficulty and an agent-based model spanned on different social network structures, we show that innovation adoption may exhibit abrupt changes in market penetration as a result of even small changes in difficulty. The latter may be of particular interest to policy makers who have to make strategic decisions when introducing socially -- but not necessarily individually -- desired products and practices, like dynamic or green electricity tariffs.