<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 att.scoping (@target, @match)
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
model.global.meta model.glossLike
May contain
certainty: certainty precision respons
core: desc gloss
tagdocs: altIdent equiv
Declaration 

<rng:element name="precision">
 <rng:ref name="att.global.attributes"/>
 <rng:ref name="att.scoping.attributes"/>
 <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,
   att.scoping.attributes,
   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"/>