Metrics:Precise
Definition
Facilitates specificity to determine whether a patient has had the requisite vaccinations for disease protection and, if not, which exact vaccinations are needed to achieve immunity.
Encoded vaccines can be characterised as concrete, when they correspond exactly to a given product, or abstract, when they represent a class of products with similar characteristics. Vaccine code systems may contain only concrete codes (such as pharmaceutical code systems), both concrete and abstract codes (CVC, NUVA), or only abstract codes (SNOMED-CT, ATC).
Rationale
Precision ensures individuals receive the necessary vaccines for full protection.
Measure
If we consider NUVA as the most comprehensive list of possible vaccine records, precision is characterized by the ability to distinguish between NUVA concepts. For each NUVA concept (within the codeable ones, see completeness), there is at least one code in the code system that matches with a minimum set of NUVA concepts. If this set is reduced to 1, then the concept designation is absolutely precise.
The overall ambiguity of the code system is then characterized as the square root of the average size of these sets for all NUVA codes. The square root is used because the size of the set impacts twice the average. With this method, if all sets of indiscriminate concepts had the same size, the ambiguity index would be equal to that size.
The precision is the inverse of the ambiguity.
The Python program described at nuva-utils computes the values for completeness and precision, based upon an alignment table between a given code system and NUVA codes. The description pages for each code (see Code systems) includes these values as computed from the currently known alignments.