AbstractThis chapter focuses on the assessment of the impacts of farmers' natural resource management (NRM) practices (and other decisions affected by NRM research) on outcomes of interest such as productivity. The first part of the chapter discusses econometric approaches to NRM impact assessment in general, their merits and drawbacks, and the types of problems that must be addressed. This is followed by an exploration of some of the key econometric issues in more detail using simple mathematical notation. An example is then presented of the use of econometric methods to assess the impacts of NRM and other factors on crop production in Uganda. Many of the approaches discussed in the preceding section are incorporated into the study, including test of multicollinearity, exclusion restrictions, relevance, and the Hausman test of consistency of ordinary linear least squares regression (OLS) vs. instrumental variables (IV) estimation. The results imply that other factors are having more impact on the value of crop production in Uganda than land management practices and most land investments, except investment in banana production. Other particularly important factors include the amount of labour used, access to agricultural extension and training, and the income strategy of the household.