====== Metrics - Inclusive ======
===== Definition =====
Does not degrade information when importing data from other code systems.
===== Rationale =====
Data from preexisting or local IIS should be imported without under no overinterpretation.
===== Possible measure =====
During our study of existing Immunisation Information Systems (IIS), we have identified 27 national systems in EU and EEAB countries, US, Canada, Australia, and Switzerland, each using its own codification.

If we add systems from non-evaluated countries and proprietary encodings that would exist in widespread electronic health records, we can assume that some 50 code systems would be needed to collect most of digital trail. 

The digital trails inclusiveness index is thus taken as the percentage of these 50 external code systems for which an unambiguous alignment is available.