Rather recently, more robust studies regarding the socioeconomic impact of certification have been published that correct for selection bias (i.e., active, better-off farmers are likely
to be among the first to participate in certification schemes)
and also consider the likelihood of substitution effects (e.g.,
with the focus on certified crops, production of other crops
or engagement in other non-farm activities might decrease).
Most studies rely on evidence from South- and Central
American countries where coffee certification started early.
Field studies from (East) Africa are more recent and pay
due attention to competing certification regimes.