As we saw with some of the examples in Table 5-1, release criteria are often written in a qualitative, subjective style that makes it difficult to know exactly what is intended and when you’ve satisfied them. To address this problem, consultant Tom Gilb has developed a notation that he calls "Planguage" (Gilb 2005). Planguage—derived from "plan + language"—permits precise specification of requirements, project business objectives, and release criteria. Here’s an example of how to express a release criterion using Planguage (Simmons 2001):
Very low frequency of failures when converting archive data files into current data formats.
Percent of conversion failures when performing ...