How do I cite a World Bank GDP figure that has a different reference year than my population figure?

Use the reference year from each source. Do not combine a 2023 GDP figure with a 2024 population estimate without noting the mismatch. Add a note: “GDP reference year 2023; population reference year 2024.”

What if the UN and the national statistical office give different population figures for the same year?

Cite both and explain the difference. The UN figure is a standardised projection; the national figure is the official count. Note which is more recent and whether the national figure includes disputed territories.

Can I use the CIA World Factbook as my primary source?

Only if the UN, World Bank, or WHO do not publish the indicator you need. The Factbook is a secondary compilation; its methodology notes are less detailed. Mark it and cross-check with a primary source.

How often should I re-verify a citation marked?

Every time you use the figure in a new article or comparison. Check the publisher’s website for the latest release. If the data has not been updated, note the previous retrieval date and add “latest available as of [date].”

Cite country data | Countries, Compared

Cite country data by recording the exact table, indicator, publisher, publication year, retrieval date, and revision status for every figure you use. The method below gives you a repeatable checklist that makes provenance visible and protects your comparisons from stale or mismatched data.

The citation checklist

Every time you take a number from a source, record six elements in a consistent format. Use this template:

Table/indicator: [name of the dataset or indicator]
Publisher: [named organisation]
Publication year: [year the data was released, not the reference year]
Reference year: [the year the data describes]
Retrieval date: [the date you accessed the source]
Revision status: if the figure is updated yearly, if the source methodology or figure is uncertain

Example:
- Table/indicator: Population, both sexes
- Publisher: United Nations Department of Economic and Social Affairs
- Publication year: 2024
- Reference year: 2024
- Retrieval date: 2026-10-15
- Revision status:

This makes it clear that the 1.4 billion figure for India is a UN projection from 2024, not a census count, and that it needs re-verification after the next UN revision.

Data source hierarchy

Not all sources carry the same authority. When you compare countries, follow this order of preference:

Primary international organisations, United Nations (population, development indices, territorial definitions), World Bank (economic data, income classifications), WHO (health metrics), UNESCO (education and culture). These publish standardised, peer-reviewed data with transparent methodology.
National statistical offices, The official census bureau, ministry of statistics, or central bank of the country in question. These are the original data collectors, but their figures may use different definitions and may be politically influenced (see “Claimed vs real” below).
Secondary compilations, CIA World Factbook, IMF, OECD, Freedom House, Transparency International. These are authoritative for specific domains (OECD for high-income comparisons, Freedom House for political rights) but are compilations of primary sources.
IANA, For time zones, country codes, and domain name assignments. These are administrative facts, not statistical estimates.

Never mix a World Bank GDP figure with a CIA World Factbook population figure without checking that the reference years match.

Population

Source: United Nations Department of Economic and Social Affairs (UN DESA), World Population Prospects.
What you get: Estimates and projections for every country and territory, by age and sex, updated every two years.
What to watch: Census data is often 2-5 years old and undercounts rural or nomadic populations. The UN figure for a given year is a projection, not a count. Mark it because the estimate changes each revision.
Example entry:
- Table/indicator: Population, both sexes, 2024
- Publisher: United Nations DESA
- Publication year: 2024
- Reference year: 2024
- Retrieval date: 2026-10-15
- Revision status:

Capital

Source: United Nations Geospatial Information Section, plus the country’s own constitution or legal code.
What you get: The seat of government, which may not be the largest city.
What to watch: Some countries (e.g., South Africa) have multiple capitals; others (e.g., Nauru) have no official capital. Disputed territories require neutral wording.
Example entry:
- Table/indicator: Capital city
- Publisher: United Nations Geospatial Information Section
- Publication year: 2024
- Reference year: 2024
- Retrieval date: 2026-10-15
- Revision status:, check for changes after political transitions

Currency

Source: IANA (for currency codes) and the country’s central bank.
What you get: Official currency name, ISO 4217 code, and symbol.
What to watch: Exchange rates change daily. Do not cite a specific exchange rate as a durable fact. Mark the currency name itself as stable (ISO codes change only when countries merge or split).
Example entry:
- Table/indicator: Currency (ISO 4217)
- Publisher: IANA
- Publication year: 2024
- Reference year: 2024
- Retrieval date: 2026-10-15
- Revision status: Stable

Language

Source: UNESCO (for official and minority languages) and the country’s constitution or language law.
What you get: Official language(s) and, where available, the most spoken vernacular.
What to watch: Official language and most spoken language may differ. Literacy rates are often based on self-reported ability, not tested functional literacy. Mark literacy figures because they are updated with each census cycle.
Example entry:
- Table/indicator: Official languages
- Publisher: UNESCO Institute for Statistics
- Publication year: 2024
- Reference year: 2024
- Retrieval date: 2026-10-15
- Revision status:, language policy can change

Visa

Source: Foreign ministries (e.g., US State Department, UK FCDO) and IATA Travel Centre.
What you get: Current visa requirements, but these change with political events and health situations.
What to watch: This page does not give visa advice. Your citation should point to the authoritative source, not to a specific policy. Mark all visa information and note the retrieval date.
Example entry:
- Table/indicator: Visa requirements for short-term travel
- Publisher: IATA Travel Centre (via Timatic)
- Publication year: 2026
- Reference year: 2026
- Retrieval date: 2026-10-15
- Revision status:, verify before use

Claimed vs real: how to flag uncertainty

Every statistic has a gap between the official figure and the lived reality. The research identifies these common gaps:

GDP growth rate, Official figures often report 1-3% higher than independent estimates; the gap widens during election years.
Unemployment rate, Official figures typically understate true unemployment by 2-5 percentage points because they exclude discouraged workers and informal employment.
Literacy rate, Official figures can be 5-15% higher than functional literacy assessments.
COVID-19 death toll, Official figures undercount true deaths by 20-60% globally.
Forest cover, Official satellite-based figures often overstate forest area by 5-10% because they include plantations.

When you cite such a figure, add a note like: “Official figure; independent estimates suggest a range of X, Y (source, year).” This makes the uncertainty visible without undermining the citation.

Confusion pairs to avoid

GDP (nominal) vs GDP (PPP), Nominal uses market exchange rates; PPP adjusts for local price levels. Always specify which you are using.
Population estimate vs census count, Estimates are projections; censuses are actual counts but occur every 5-10 years.
Life expectancy vs healthy life expectancy, Life expectancy is total years; healthy life expectancy subtracts years with illness.
Literacy rate vs functional literacy rate, Literacy rate measures basic ability; functional literacy measures everyday reading ability.
Country vs territory, A country is a sovereign state; a territory is non-sovereign. Use UN membership as the default definition.

Revision statuses explained

Every citation gets one of these:

****, The figure is updated at least once a year (GDP, population estimates, inflation, visa policies). Re-verify before using in a new context.
****, The figure is from a lower-confidence source, uses a different methodology than the standard, or refers to a disputed territory. Check the original source and note the uncertainty.
Stable, The fact changes only when countries merge, split, or change their legal framework (ISO codes, capital cities, official languages). These can be reused without re-verification for several years, but check the retrieval date.

Putting it together: a full example

You want to cite India’s population for a comparison with China.

Table/indicator: Population, both sexes, 2024
Publisher: United Nations Department of Economic and Social Affairs
Publication year: 2024
Reference year: 2024
Retrieval date: 2026-10-15
Revision status:
Value: 1.450 billion

Then add a note: “UN projection; last census was 2011. Official census count for 2021 was delayed.”

This gives your reader the exact provenance, the uncertainty, and the next check date.

Cite country data