# **3 Experimental design and implementation**

## **3.1 Experimental design**

We conducted a randomized evaluation of a traction oxen matching grant for cotton farmers working under formal cotton societies in four northern regions of Cˆote d’Ivoire under the World Bank’s Agricultural Support Program (PSAC).<sup>6</sup> Specifically, the project provided a matching grant of 50% of the cost of receiving two traction oxen and related equipment, with producers financing the remainder through their own funds or credit from cotton ginning companies and agricultural cooperatives.<sup>7</sup> In economic terms, this is a large treatment. Previous studies have found that an ox provides farm ‘labor’ equivalent to five to eight men, and that traction oxen are at least twice as powerful as smaller bovines: 400-500 watts of power versus less than 200 watts for small bovines (Smil, 2004; Starkey and Faye, 1990).

The participant cotton societies formed the farmer sampling frame using their member lists and a mix of objective criteria (such as being married, having been a member of a cotton society for at least 3 years, and belonging to a single cotton society) and more subjective criteria determined by cotton society staff (being credit-worthy, trust-worthy, and able to increase their cotton farmland). Few farmers in the sampling frame owned traction oxen before the intervention, although many owned other types of farm equipment (Appendix Table B1).

We used a randomized phase-in approach for our experiment: from an initial sample frame of 2,546 eligible farmers, we randomly assigned 1,273 producers to receive the oxen matching grant offer in the fall of 2016 (treatment group) and 1,273 to receive the offer starting in April 2018 (control group). We stratified the randomization by cotton zone, whether the cotton societies’ administrative data indicated that they already owned any oxen, whether they requested one or two oxen, and whether they owned a cart. We measure impacts using detailed household surveys conducted in July and August 2018.<sup>8</sup> As cotton cultivation is a key outcome of interest in this experiment, Figure 1 presents the timing of the distribution of the oxen under the experiment together with the key activities of the 2017 and 2018 cotton

> 6The cotton component of the project operated in Bere, Poro, Tchologo and Worodougou, and partnered with Intercoton—the cotton value-chain interprofessional organization in Cˆote d’Ivoire—and its five constituent cotton societies (CIDT, COIC, IVOIRE COTON, SECO and URECOSCI) to implement the matching grant intervention under the broader goal of increasing agricultural productivity in the country.

> 7The market value of two traction oxen at the time of delivery was FCFA 480,000, implying a matching grant value of FCFA 240,000 (US $408). In practice, there are small variations in treatment across farmers. While 96% of farmers requested two oxen, 4% instead requested one ox: households assigned to the treatment group were provided with the opportunity to purchase their requested number of oxen. Moreover, 7% of farmers in the treatment group requested and received a multicultivator, 6.4% a seed drill, 5.1% a plow, and less than 3.5% a received tillers or carts. Appendix Table B1 provides a full list, and shows that households own an average of 2 pieces of equipment, irrespective of their treatment status. The most commonly owned tools are multicultivators (52% households), followed by carts (46%) and plows (43%).

> 8We only collected information on agricultural inputs use from a random half of the sample, due to budgetary reasons. The data is balanced across this split.

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