We propose an approach to knowledge-based decision-model construction. The domain knowledge is represented in the form of multilevel influence diagrams. At each level, a regular influence diagram representing a decision model may be generated and the influence diagrams between the levels are related through a series of operations. We defined eight such operations and show that these are sufficient at the structural level to construct any target influence diagram in any practical situation. We provide a series of examples drawn from different domains on the use of multilevel influence diagrams for model construction. We also propose suggestions on providing users with guidance that can direct the model-construction procedure towards the best target model.