Research
This paper examines the effectiveness of nudges in promoting the adoption of improved sweet potato varieties among smallholder farmers in Uganda. The study uses a randomized controlled trial design, with a sample of 1,133 farmers divided into a control group and three treatment groups that receive different nudges, including posters and text reminders. The nudges are designed to address specific behavioral barriers to adoption, such as limited awareness of the benefits of improved varieties and the tendency to stick with traditional practices. The study finds that nudges are effective in increasing the adoption of improved varieties, with the most effective nudge being a combination of social comparison and emotional appeals. Specifically, the likelihood of households purchasing improved varieties increased by 6.5% when provided with behavioral nudges. The study also finds that the nudges are particularly effective for farmers who are less educated and have smaller landholdings. We find compelling evidence for heterogeneous treatment effects, with robust treatment effects among those who experienced a stronger emotional connection to the nudges that we deployed. A key concept to help explain this is nostalgia: farmers prone to nostalgia responded more strongly to the traditional farming imagery used to nudge the adoption of improved varieties.
Nudging the Adoption of Improved Crop Varieties: Evidence From a Large Randomized Controlled Trial in Uganda
with Julius Juma Okello, David Ryan Just, Arjan Verschoor, Sylvester Okoth Ojwang, Janet Mwende Mutiso, Chalmers Kyalo Mulwa, Sam Namanda, Srinivasulu Rajendran, Reuben Tendo Ssali, Moses Okim, Hugo Campos
This study advocates for the adoption of climate-sensitive bonds as a financial strategy to address the impacts of climate change and its fluctuating patterns. We introduce two novel modeling approaches: the Ornstein-Uhlenbeck (OU) process and the Scaled Variance Ratio method, to calculate the Hurst coefficient—a measure traditionally applied in hydrology—that aids in understanding the variance properties of climate change. Theoretically, we establish a clear link between the OU process and the Hurst coefficient, demonstrating that any mean-reverting OU process can be distinctly characterized by this single-index Hurst measure. Empirically, we utilize 0.5°×0.5° gridded climate data from the United States, covering 1901 to 2021, sourced from the University of East Anglia and NOAA weather station records, to calculate the Hurst across the US.
Figure 3: Hurst measures for average monthly temperature using the Variance Ratio.
Figure 4: Hurst measures for average monthly temperature using OU approach
The findings indicate that climate change in the U.S. exhibits a high level of ergodicity, implying that variance has been stable or increased only slightly. This is evidenced by Hurst coefficients ranging from 0 to approximately 0.3 across the majority of the studied grids, suggesting a consistent or slightly increasing variability in the observed climate patterns. We suggest that climate bonds linked to climate variables such as temperature and rainfall can take on characteristics similar to catastrophe bonds. We also explore the potential of financial products, such as bonds with call or put options, based on temperature or precipitation.