Addressing endogeneity in climate-smart technology adoption: The role of extension and credit among vanilla farmers in Morogoro-Tanzania

Climate-smart agricultural (CSA) technologies are vital for enhancing the climate resilience of high-value, climate-sensitive crops like vanilla in Sub-Saharan Africa. While institutional support through agricultural extension and formal credit is widely promoted to drive CSA adoption, empirical evidence of their causal impact is frequently biased by endogeneity from farmers' non-random access to these services. This study investigates the determinants of CSA technology adoption among smallholder vanilla farmers in Tanzania's Morogoro region, explicitly addressing the endogeneity of extension access. Employing an instrumental variable probit (IV-Probit) model with data from 270 farmers, the study uses distance to extension offices and access to demonstration plots as instruments. The IV-Probit model was chosen over other models because it is best suited for analyzing a binary adoption decision while effectively correcting for endogeneity. The results confirm that access to extension services is endogenous and is the most significant driver of adoption. Female farmers, married households, access to credit, off-farm income, livestock ownership, higher income, and a risk-tolerant attitude also significantly increase the likelihood of adoption. Female farmers and married households are more likely to adopt climate-smart technologies due to differences in social capital, access to labor, and risk preferences, where marital status often enhances labor availability and resource pooling, while gender influences access to information, credit, and decision making power. The findings underscore that adoption is driven by a combination of robust institutional support, economic capacity, and household characteristics. The study concludes that scaling CSA in perennial crops with long gestation periods, such as vanilla requires integrated policies such as Agricultural Sector Development Programme II and National Climate Change Strategy that strengthen targeted, gender-responsive extension systems, improve financial inclusion, and address behavioral barriers to reduce investment risks and foster sustainable climate adaptation.