MIGRATION THEORIES AND EVIDENCE: AN ASSESSMENT

Abstract. This paper presents a critical survey of theories of migration, their welfare and policy implications and their empirical relevance. We also develop some extensions to the theory beginning with the Harris and Todaro (HT) model. In particular, the HT model is extended to examine risk averse behaviour within families where the migration of members of families serves to diversify risk. The welfare implications of the individual migration decision and government intervention in the form of employment subsidies are examined. Recent evidence on international migration is presented. It is shown that migration does not flow automatically in response to wage differentials. Characteristics of migrants and the process of self-selection are found to be important determinants of the rate of migration.     

Pesticide use in less developed countries — economic and environmental considerations

This paper examines the use of pesticides in the agriculture of less developed countries (LDCs). It outlines in general terms both the benefits and the costs of any pesticide programme and the difficulties involved in the quantification of cost functions are highlighted. A number of conclusions are reached at the general policy level. Selective pesticide applications can be justified in a number of cases where the benefits are clearly outstanding. However, the social costs involved in pesticide usage require careful consideration. Given the scarcity of resources and foreign exchange in LDCs, extreme caution is needed. It would appear that increased pesticide inputs have only a marginal effect on total output and employment, and other inputs (ie better seeds, irrigation schemes, etc) may yield more significant results.