<precision>

<precision> indicates the numerical accuracy or precision associated with some aspect of the text markup.
Module certainty — 21 Certainty, Precision, and Responsibility
In addition to global attributes In addition to global attributes
target points at the element or elements the precision of which is to be specified.
Status Optional
Datatype 1–∞ occurrences of 

<rng:ref name="data.pointer"/>
data.pointer
separated by whitespace
Note
If more than one identifier is given, the precision element is interpreted as applying to all.
match supplies an XSLT 2.0 pattern which may be used to select those portions of the document the precision of which is to be specified.
Status Optional
Datatype

<rng:text/>
text
Values The pattern should be expressed using the pattern syntax defined in Kay (ed.) (2007).
Note
The context for the pattern is the nodeset identified by the value of the target attribute. If no value is given for target, the context is the document root element.
Note that the value of the target attribute may include an XPointer expression which may include an XPath expression (see 16.2.4 TEI XPointer Schemes). Either method may be used to identify the parts of a document whose precision is to be documented by this element.
degree indicates the degree of precision to be assigned as a value between 0 (none) and 1 (optimally precise)
Status Optional
Datatype

<rng:ref name="data.probability"/>
data.probability
stdDeviation supplies a standard deviation associated with the value in question
Status Optional
Datatype

<rng:ref name="data.numeric"/>
data.numeric
Used by
May contain
core: desc gloss
tagdocs: altIdent equiv
Declaration

<rng:element name="precision">
 <rng:ref name="att.global.attributes"/>
 <rng:optional>
  <rng:attribute name="target">
   <rng:list>
    <rng:oneOrMore>
     <rng:ref name="data.pointer"/>
    </rng:oneOrMore>
   </rng:list>
  </rng:attribute>
 </rng:optional>
 <rng:optional>
  <rng:attribute name="match">
   <rng:text/>
  </rng:attribute>
 </rng:optional>
 <rng:optional>
  <rng:attribute name="degree">
   <rng:ref name="data.probability"/>
  </rng:attribute>
 </rng:optional>
 <rng:optional>
  <rng:attribute name="stdDeviation">
   <rng:ref name="data.numeric"/>
  </rng:attribute>
 </rng:optional>
 <rng:zeroOrMore>
  <rng:ref name="model.glossLike"/>
 </rng:zeroOrMore>
</rng:element>
element precision
{
   att.global.attributes,
   attribute target { list { data.pointer+ } }?,
   attribute match { text }?,
   attribute degree { data.probability }?,
   attribute stdDeviation { data.numeric }?,
   model.glossLike*
}
Example
<date xml:id="date001" notBefore="0014" notAfter="0064">About 50
years after the death of Augustus</date>
<precision target="#date001" match="@notAfter" degree="0.3"/>
<precision target="#date001" match="@notBefore" degree="0.9"/>