As the use of formal specification techniques becomes more widespread,
it becomes more important than ever to ensure that the formal specifi
cation of a system is a faithful representation of the system's requir
ements, CASE tools can help with this problem by performing mechanical
analysis of the specification. The paper describes the scope and limi
tations of one such tool for the specification language VDM-SL, based
on two case studies, and compares the use of this tool to other valida
tion techniques.