Within a Bayesian framework, a random-effects model is developed and a
pplied to adoption of new wheat varieties in South Australia. In this
model, not all pieces of information add equally to knowledge about th
e innovation. The model shows the acquisition of information to be muc
h slower than has been suggested by previous Bayesian models and can a
lso explain laggards and partial adoption. The results have important
practical implications for farmers and support agencies. The paper's t
heoretical contributions are to highlight the structure of information
, and to demonstrate how qualitative results can be obtained where the
posterior Bayesian distribution is intractable.