The shape persistence of a crop yield
probability density function (PDF) was studied by using
two variants of the Visual Impact Method (VIM) to elicit
subjective estimations by farmers. In one variant ten
weights were used to describe the PDF and in the other
variant the farmer chose the number of weights. Results
were compared directly and by means of Weibull
distributions fitting, with evidence being obtained in
favor of methodological persistence and the equivalence
of the two estimation methods