Dear Laurel, Nick, Roger, Joao Pedro, Giogio and Todd,
Many thanks for your comments. To put things in perspective, the presenter
was studying new maize varieties and sought to identify some socio economic
factors that may explain the adoption of these varieties. All respondents in
her sample grew some maize (traditional, improved or both) so her dependent
variable was area under improved varieties (which would then be handled
easily in a censored regression framework or better still as a corner
solution outcome). However, she argued that the area allocated needed to be
adjusted for total area under maize (if one has 1 acre and allocated 0.5
acres to the maize then in terms of adoption, this should not be the same as
someone with 10 acres of maize land but also allocates 0.5 acres) hence the
dependent variable was total area under new maize/ total maize area (hence
the proportion).
