Compare geographic coverage

Do identically named areas cover the same units?

A label defines neither a boundary nor a population. M49 classifies statistical units; a map layer supplies geometry. Link classification, layer and indicator coverage explicitly.

1. Identify classification

   Keep code as text, level and version. Retain leading zeros; do not equate M49, ISO and NUTS codes by appearance.

2. Check membership

   List members and exclusions for each aggregate. Changed membership can change a total while national series remain unchanged.

3. Handle changes

   Check mergers, splits and boundaries during the period. A correspondence needs direction, validity and multiplicity; one old code can map to several new ones.

4. Validate joins

   Check duplicates, unmatched units and level. Never add an aggregate and its members together; maps also need coordinate system and layer date.

Situations and decisions

Typical situations for preparing a check. They do not describe completed assignments or actual observations.

Record to retain

• Code, label, level and classification version.
• Membership, exclusions and validity period.
• Correspondence direction and any weights.
• Unmatched units and treatment method.

Official references

• UNSD — M49 methodology
• Eurostat — NUTS history

Related source profiles

• UNSD — M49
• Eurostat · Data Browser
• UN System Data Commons
• World Bank Open Data
• OECD Data Explorer
• cartes.gouv.fr
• OpenStreetMap
• FAOSTAT
• ILOSTAT
• UNHCR · Operational Data Portal

Related protocols

• Check a join before combining two files
• Check a statistical series break
• Build a usable data dictionary

Checks before reaching a conclusion

• Do levels match?
• Is membership dated?
• Are multiple relationships explicit?
• Are aggregates and members counted separately?