  We present a model for the diffusion of management fads and other
technologies which lack clear objective evidence about their merits. The
choices made by non-Bayesian adopters reflect both their own evaluations and
the social influence of their peers. We show, both analytically and
computationally, that the dynamics lead to outcomes that appear to be
deterministic in spite of being governed by a stochastic process. In other
words, when the objective evidence about a technology is weak, the evolution of
this process quickly settles down to a fraction of adopters that is not
predetermined. When the objective evidence is strong, the proportion of
adopters is determined by the quality of the evidence and the adopters'
competence.
