Indicates the degree of precision of the data element definition.
This value set has an inline code system http://hl7.org/fhir/dataelement-stringency, which defines the following codes:
| Lvl | Code | Display | Definition |
| 1 | comparable | Comparable | The data element is sufficiently well-constrained that multiple pieces of data captured according to the constraints of the data element will be comparable (though in some cases, a degree of automated conversion/normalization may be required). |
| 2 | fully-specified | Fully Specified | The data element is fully specified down to a single value set, single unit of measure, single data type, etc. Multiple pieces of data associated with this data element are fully comparable. |
| 2 | equivalent | Equivalent | The data element allows multiple units of measure having equivalent meaning; e.g. "cc" (cubic centimeter) and "mL" (milliliter). |
| 2 | convertable | Convertable | The data element allows multiple units of measure that are convertable between each other (e.g. inches and centimeters) and/or allows data to be captured in multiple value sets for which a known mapping exists allowing conversion of meaning. |
| 3 | scaleable | Scaleable | A convertable data element where unit conversions are different only by a power of 10; e.g. g, mg, kg. |
| 1 | flexible | Flexible | The data element is unconstrained in units, choice of data types and/or choice of vocabulary such that automated comparison of data captured using the data element is not possible. |