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type: datatypedatatype: Ratio

Ratio

Overview

See also Examples, Detailed Descriptions, Mappings, Profiles and Extensions

A relationship between two Quantity values expressed as a numerator and a denominator.

The Ratio datatype should only be used to express a relationship of two numbers if the relationship cannot be suitably expressed using a Quantity and a common unit. Where the denominator value is known to be fixed to "1", Quantity should be used instead of Ratio.

[%dt Ratio 6%]

Examples where a Quantity is typically used are rates, densities, concentrations. Examples where a Ratio is used are: titers (e.g., 1:128); concentration ratios where the denominator is significant (e.g., 5mg/10mL); observed frequencies (e.g., 2 repetitions/8 hr), and where the numerator or denominator is an amount of a currency (no UCUM code for $ etc.).

Common factors in the numerator and denominator are not automatically cancelled out. Ratios are not simply "structured numbers" - for example, blood pressure measurements (e.g., "120/60") are not ratios.

A proper ratio has both a numerator and a denominator; however, these are not mandatory in order to allow an invalid ratio with an extension with further information.

Constraints

[%dt.constraints Ratio%]

The context of use may require particular types of Quantity for the numerator or denominator.

Ratio is used in the following places: [%dtusage Ratio%]

Elements

Mappings