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):

In Planguage, each release criterion receives a unique tag or label. The ambition describes the goal you’re trying to achieve. Scale defines the units of measurement and meter describes precisely how to perform the measurements. One great benefit of Planguage is that you can specify several target values. The must criterion is the minimum acceptable achievement level for the item being defined. You haven’t satisfied the release criteria unless all "must" conditions are completely met. The plan value is the nominal target and the wish value represents an ideal outcome. Expressing your product release criteria using Planguage provides a precise and explicit way to know whether your product is ready to go out the door.