programs also vary as some programs were evaluated based on randomized trials, while others are observational studies.

One of the primary objectives of input subsidy programs is technology adoption to increase agricultural productivity. Specifically, input subsidies can begin a ‘virtuous cycle’ for farmers to adopt new technology or better farming practices. Some programs provide fertilizers and improved seeds to allow farmers to learn through experience, while others include agricultural extension services to encourage good farming practices. Some fertilizer subsidy programs provide free distribution or full subsidy, so that farmers have no out-of-pocket payments, while others provide partial subsidy, thus requiring farmers to share the cost of the fertilizer. The distortion due to subsidies can lead farmers to use suboptimal input mix, which may lead to no productivity gain, or even a reduction in productivity. Additionally, overuse of fertilizer may generate a negative environmental externality, which can then lead to water pollution, which subsequently can adversely affect health outcomes (Brainerd and Menon 2014; Zaveri et al. 2020). In this study, we focus on the effect of agricultural input subsidies on productivity. Another common policy objective of agricultural subsidy programs is poverty reduction. By targeting the subsidy to poor farmers, their productivity increase could also increase their income and living standards. At the aggregate level, this could then lower poverty. To examine living standards, our secondary outcome of interest is farming household income or expenditure to capture living standards.

We initially identified 655 articles for title and abstract screening. After the full text screening, 12 studies were used in the meta-analysis regression. Based on these articles, we find that input subsidy programs are associated with an 18% increase in yield. While this suggests an improvement in production per unit of cultivated land, we are unable to examine the overall productivity impacts (i.e. total factor productivity), nor the external impacts such as environmental externalities. For our secondary outcome of interest, we find that input subsidy programs are associated with a 16% increase in farming household income or expenditure, which suggests that the increase in yields translates to improvements in living standards. The analysis includes four articles from Malawi, so we perform back-of-the-envelope calculations based on our estimates and Malawi’s input subsidy program costs. In this example, we find a benefit-to-cost ratio of 1.2, which implies that a $1 subsidy is associated with $1.20 of benefits.

# **2. Data and methods**

A meta-analysis begins with a database search—based on pre-identified keywords—using at least two databases, followed by title and abstract screening, full text screening, and finally the meta-analysis regression. For the database search, we used a query search in the three following databases: _Web of Science_ , _Scopus_ , and _jstor_ . The search is restricted to articles in Economics published between the years 2000 and 2021.<sup>4</sup> We further restrict the setting to low- and middle-income countries based on World Bank classification. Observational studies and experiments are included in this meta-analysis since few studies using experimental evidence are available. The keyword search generally aims to search for input subsidy programs in agriculture and their impacts on productivity or income or expenditure. We

> 4 While it is possible to examine studies from before 2000, we believe more recent studies would be more similar to current policy settings.

3