Identifies why this milestone exists, what problem it is solving, and/ or what object cannot be modeled using the regular hierarchy.
Best Practice: Although not required by the Tag Set, this should be treated as a required attribute and a value always provided when milestones are used.
| Value | Meaning |
|---|---|
| Data characters | Text, numbers, or special characters. |
| Restriction: This attribute may be specified if the element is used. | |