A formal specification is beyond the comprehension of the average software customer. As a result, the customer cannot provide useful feedback regarding its correctness and completeness. To address this problem, we suggest the formalism expert to work with the customer to create precise scenarios. A precise scenario describes an operation by its effects on the system state with only few simple Z
concepts. The customer would find a concrete precise scenario easier to understand than its corresponding abstract schema. The Z expert derives schemas based on the precise scenarios. Precise scenarios affords user involvement that improves the odds of a formal specification fully capturing the user requirements
