Les effets sur le bien-être de politiques agricoles et de changements de prix en Tanzanie dépendent de la capacité des ménages à ajuster leurs comportements

17 Décembre 2014

Dans un article à paraître dans la revue Journal of African Economies, Luca Tiberti (PEP et CIRPÉE) et Marco Tiberti (University of Florence et World Bank) étudient les effets de politiques rurales et des changements de prix en Tanzanie à l’aide d’un modèle de ménages agricoles. Voici l’abstrait (en anglais) :

Exogenous shocks to farmers’ consumption, production and labour market decisions are rarely considered accurately. For farm households, under labour market imperfections, such decisions are often interlinked. This calls for non-separable agricultural household models. According to this framework, second-order (or behavioural) effects include a direct (i.e. supply or demand reactions due to an exogenous shock) and an indirect (i.e. supply or demand adjustments to the endogenous variations in the shadow wage generated by the exogenous shock) component. Under large price changes or following structural interventions, such as those concerning land redistribution or mechanization practices, neglecting such second-order effects on consumption and production can bias the final impact on household welfare. The main objective of this study is thus to develop a robust and comprehensive tool to evaluate the effect on household welfare of different agricultural policies in Tanzania and food price changes. A two-stage estimation strategy is adopted: the shadow price of labour is first estimated and then used to estimate production and demand systems as well as labour market functions. These models are subsequently used to simulate the effect on household welfare of a hypothetical 40% increase in the price of cereals and other crops and a hypothetical 10% increase in the hectares of arable land and in the use of ox ploughs. The results are finally compared with the case in which a separable model is adopted.