This paper discusses the process of appropriate problem formulation to identify data needs as a preliminary step in risk assessment of genetically modified crops (i.e. identification of the protection goals of the law or other instrument that triggered the risk assessment; recognition of adverse effects as operational assessment endpoints following problem formulation; development of possible scenarios of harm; and formulation of testable hypotheses and determination of an experimental plan to test them), and describes the application of this strategy in risk assessment of transgenic sorghum (Sorghum bicolor) in Africa.