In the case of agroforestry, rural people can be part of the system as well as active observers, recorders, analysts, evaluators and independent experimentors.
They may monitor and evaluate projects and research process as
well as specific technologies [Davis-Case, 1989]. They can also conduct their
own "perturbation experiments" with "real world" models to observe the
response of agroforestry systems to specific changes. The "control" is in their
memory. This type of experiment may actually prove more coherent from
their point of view than a replicated experiment laid out in blocks.