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Turn a question into a clearer picture.

Explore how countries change over time, compare their trajectories, and check the evidence behind the numbers.

1. Choose a country and a year

Start in Countries and search by name or ISO code. On a country page, move the year slider to see the metrics available for that year. An unavailable value means the evidence has a gap; it does not mean zero.

2. Follow a metric through time

Select a metric name to open its chart. Use the date filters to focus on a period, or add related metrics to view separate charts with synchronized highlighting. Open “Data and evidence” to inspect individual values and their provenance.

3. Make a fair comparison

On Compare, choose up to eight countries and four metrics. Start with two countries and one metric to keep the chart easy to read. Check units, periods and source definitions before drawing conclusions.

Absolute value

Compare levels in the metric’s unit. Large economies may have larger totals without higher values per person.

Indexed change

Each country’s first available value in the selected range becomes 100. Use this to compare proportional change. Countries may start in different years, so check their first available periods.

Year-over-year change

Compare a value with the same period one year earlier. A missing matching observation leaves a gap.

Five-year moving average

Smooth annual volatility using the current and preceding four years. A complete five-year window is required.

Try a question

“Has population grown at the same pace in these countries?” Choose population in Compare, select your countries and date range, then switch between absolute and indexed views. The first shows scale; the second shows relative growth. Availability depends on the observations imported for each country.

4. Check before sharing

Record the metric, country, period, unit and selected source alongside your finding. Copy the filtered page URL to preserve your selection. Read the data reading notes for limitations and interpretation.