Summary

When natural language isn't good enough, your team may apply technical methods to reduce the risk of misunderstanding and to thereby provide additional safety, security, and reliability for your system. In general, technical methods should be used sparingly, and common sense should guide the decision as to which formal technique will be used in a particular project. If you're building a nuclear reactor control system, perhaps every aspect of the system is critical; in most systems, however, it's unlikely that more than 10 percent of the requirements will require this degree of formality . Choose the method that suits your team best and apply it only where it is really needed.