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First, define who is being counted
Before looking up a population figure, decide which population concept answers your question. The South Korea Statistics service presents KOSIS resident registration population data. This administrative measure excludes foreign residents; it should not be described as a complete count of everyone living in the country.
A number from another source may use a different population definition or reference period. If two figures differ, first compare their coverage and dates. A resident registration total and an international midyear population estimate can both be useful while describing different things.
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Choose a national view or a regional profile
Start with the population overview when you need the national context. Use the regional directory to find a particular area and open its profile for local detail. A ranking is useful for locating areas with larger populations or different growth rates, but a profile gives the context needed to interpret that position.
Compare places at a matching administrative level and check their names carefully. A province and a city within it do not represent equivalent areas. Avoid adding a larger area's total to the totals of its constituent areas, because that can count the same people twice.
- Population overview: begin with the national total and reporting period.
- Regional profiles: examine a specific area's population over time.
- Population ranking: compare the size of areas within the listed scope.
- Growth ranking: explore relative changes, then inspect the underlying counts.
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Keep reporting months and intervals aligned
The service uses monthly data. Write down the selected month alongside any value you save. A change from one month to the next answers a different question from a change against the same month a year earlier, so check the interval displayed by the page.
Use matching months when comparing regions. If a source or page does not provide an observation for the period you need, preserve that gap. Substituting an older observation without noting the date can turn a timing difference into an apparent regional difference.
Synthetic monthly-change example
An invented region rises from 500,000 registered residents in one month to 502,000 in the next. The absolute increase is 2,000. The relative increase is 2,000 ÷ 500,000 × 100 = 0.4%. This calculation describes that one-month interval; it is not an annual growth rate.
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Read growth together with population size
Population rankings and growth rankings answer different questions. A large region can gain more residents in absolute terms while showing a smaller percentage increase than a small region. Read both the starting population and the change before describing one area as growing faster.
Synthetic ranking example
Region A grows from 20,000 to 20,400, an increase of 400 or 2%. Region B grows from 1,000,000 to 1,010,000, an increase of 10,000 or 1%. A has the larger percentage increase; B adds more registered residents. These invented figures show why the ranking measure matters.
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Keep the definition with the conclusion
A change in registered population does not explain its cause by itself. Births, deaths, migration, registration changes, and administrative boundaries can affect interpretation. Check the underlying source notes before attributing a movement to a single cause or comparing a region across boundary changes.
For a reproducible note, keep the area name, population definition, reporting month, comparison interval, and KOSIS source together. State explicitly that foreign residents are excluded from this resident registration measure. For an international comparison, move to Global Data and choose a consistent international indicator for both countries.