Korea, explained through data
A guide to reading data
The same number can tell different stories depending on its context. Start with these three principles, then explore the topics that interest you.
Three principles for reading numbers
First, what does the number count?
A publication date is not a reporting period. Check the region, whether a figure counts people or events, and whether it is cumulative or weekly. Comparing figures with different scopes or periods can change the conclusion.
Percent is not percentage points
If a hypothetical rate rises from 20% to 25%, the difference is 5 percentage points. The relative increase is (25 − 20) ÷ 20 × 100 = 25%. This formula cannot calculate a relative increase when the starting value is zero.
Moving together does not establish a cause
Falling album sales alongside a higher overseas ranking do not, by themselves, prove that fans changed how they spend. Sales and ranks measure different things. Separate observations from possible explanations and look for evidence that could test those explanations.
Work it out: a 75% rise, but a lower daily average?
Use fictional exhibition attendance counts to see how reporting periods affect a comparison. These numbers are made up for this example, not results from a real exhibition or work. One person may attend more than once, so attendances are not unique visitors.
| Period | Attendances | Days counted | Attendances per day |
|---|---|---|---|
| First period | 120 | 3 | 40 |
| Next period | 210 | 7 | 30 |
Comparing totals gives +75%
(210 − 120) ÷ 120 × 100 = 75%. Total attendance increased, but the reporting period also grew from 3 to 7 days. This alone does not establish a 75% rise in demand.
Comparing daily averages gives −25%
120 ÷ 3 = 40 attendances per day; 210 ÷ 7 = 30 per day. (30 − 40) ÷ 40 × 100 = −25%. Expressing both totals in the same daily unit changes the comparison.
A daily average is still not a final verdict. Weekend shares, opening hours, closure days, and an opening-day effect may differ. This table cannot explain why the average fell or how unique visitor numbers changed. Compare daily records with matching weekdays and opening hours.
Apply this to an article: what was counted → over which dates → whether the calculation uses comparable units → what remains unexplained.
Explore by topic
Korea by the numbers
Economic, social, and policy shifts, with the context and comparisons behind the figures.
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What film, TV, and music rankings, sales, and viewing metrics can—and cannot—tell us.
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