Table 4.

Description of temporal elements specification by five clinical information models. The description includes the elements of representation and the operators.

Temporal element / aspect	Point in time	Duration	Intervals	Periodic time	Cumulative periodic time
Model
HL7 V 3	Compatible with ISO 8601 standard. Canonical format: YYYY-MM-DDThh:mm:ss. Time zones: “+hh:mm”, “− hh:mm” relative to UTC. Operators: = =,+,−.	Is a Physical quantity of time, measured by seconds, minutes, hours, days, months and years.	Provides choices between: open interval, closed interval, high open, high closed, low open, low closed.	Use Period (derived from mathematical modulus) and phase (derived from mathematical remainder) to represent periodic points and intervals in time.	Represented using Union (∪) and or Intersection (∩) of periodic times
QDM	Derived from ISO 8601:2004. Format: Date/Time stamp from calendar: my/mm/did/hh:mm:so	Use DateTimeDiff function, which returns the quantity of time between two points.	Covers 25 different temporal operators between intervals.	N/A	N/A
CEM	Use the ISO 8601 format with the syntax: YYYYMMDDHHMMSS. UUUU [+|−ZZzz] Operator: >, <, >=, <=	It’s a Physical Quantity (PQ), which has a value and unit.	Represents closed interval of physical quantities by using properties, Low and High.	Represented by Ratio Physical Quantity with a numerator and denominator	N/A
OpenEHR	Represents absolute time as Conform to ISO 8601. Allow missing information to represent approximate time stamps.	Represents period of time in customary format, i.e. days, hours, minutes etc.	Derived from a generic interval defined for physical quantity package	Loosely expressed by common specifications.	N/A
caDSR CDE	Time and Date from calendar.	It’s a length of time between specified events.	Represented by Time or Time/Date.	Limited to specific information about frequency such as daily, weekly.	N/A