2. The method of claim 1 , further comprising: parsing the markup language of the taxonomy document to identify a concept element having a preferred label role value indicating that facts associated with the concept are in a calculation relationship, wherein parsing the markup language of the instance document comprises parsing the markup language of the instance document to identify facts tagged with the identified concept.
2. The method of claim 1 , further comprising: parsing the markup language of the taxonomy document to identify a concept element having a preferred label role value indicating that facts associated with the concept are in a calculation relationship, wherein parsing the markup language of the instance document comprises parsing the markup language of the instance document to identify facts tagged with the identified concept. 3. The method of claim 2 , wherein the value of the preferred label role represents a period start or a period end; and the calculation relationship is a roll-forward arithmetic relationship.