The fieldwork is based on two rounds of data collection, visiting the same farmers in 2009 and 2013. The initial sample size
from each of the certified cooperatives included 80–100 farm
households from both treatment groups.
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One of the treatments—Ndumbericooperative—became early engaged with
certification and carries now both Fairtrade and Utz labels,
while the second treatmentKiambaacooperative received some
three years ago its Fairtrade certification. Given the need for
matching, a larger number of 120 households were selected
from the non-certified Mikaricooperative as control group.
For reasons of comparability, the selected non-certified cooperative had similar characteristics in terms of number of wet mills,
membership and governance structures. For the second round
of data-collection in 2013, all farmers that participated in the
first round were revisited. From the 300 farmers that were interviewed in the first round, a total number of 218 could be revisited.Table 1offers an overview of the sample composition and
the certification background of each of the cooperatives