Correlation is a pattern: two variables move together. Causation is a claim that one change produces the other. Data can show the first, but the second needs an explained mechanism and a check on other explanations.
Examination questions in inflation and unemployment often show two series and a statement. Your task is to decide how far the evidence supports it.
How do you test a claim?
Use three challenges, then conclude carefully.
- A third factor: could something else be driving both variables?
- Reverse direction: could the effect actually be the cause?
- Coincidence or short data: are there enough observations, or is the match accidental?
Then write a conclusion that states what the data shows, what it does not show, and what extra evidence would help.
Worked example
A commentator on the fictional economy of Merbau writes: “Falling unemployment caused higher inflation.” The data are:
| Year | Unemployment rate | Inflation rate |
|---|---|---|
| 1 | 8% | 1% |
| 2 | 7% | 2% |
| 3 | 6% | 3% |
| 4 | 5% | 4% |
| 5 | 4% | 5% |
Step 1, describe the pattern. Each year unemployment falls by 1 percentage point while inflation rises by 1 percentage point. The two move in opposite directions: a negative correlation.
Step 2, check the mechanism. One possible story: lower unemployment raises incomes and demand, which may raise prices. That mechanism is plausible, so the claim cannot be dismissed outright.
Step 3, third factor. A rise in export orders could raise firm demand for workers and also raise prices of goods in short supply. Both series would move without one causing the other.
Step 4, reverse direction. Rising inflation could change firm behaviour in ways that affect hiring. The data alone cannot show the order of events.
Step 5, sample. Five years is a short run. A match this regular in five points may not continue.
Step 6, conclusion. “The data show unemployment and inflation moving in opposite directions over five years, which is consistent with the claim, but it does not prove it. More years, data on demand and export orders, and a check on timing would be needed.”
The mistake to watch for
Mistaken answer: “The table proves that falling unemployment caused inflation to rise.”
The student read a perfect pattern as proof. The pattern could have a third cause, run the other way, or be a short coincidence.
The correction is to replace “proves” with “is consistent with”, then name one alternative from the case.
Check yourself
1. In a fictional town, ice-cream sales and sunburn cases both rise in the hot months. A writer says ice cream causes sunburn. Name a third factor.
Show answer
Hot, sunny weather increases both ice-cream sales and time spent in the sun, so sunburn cases rise.
2. A claim says “high prices cause low unemployment”. What alternative direction could be checked?
Show answer
Reverse direction: low unemployment could raise demand and so push prices up. The sequence of events would need checking.
3. Why is a pattern across three years weak evidence for a lasting cause?
Show answer
Three observations are a short sample, so the match could be coincidence or reflect a temporary event. More years and other economies would strengthen or weaken the case.
Where this leads next
Practise this skill with real-looking tables in the mixed practice set, then move on to public finance and economic instruments. The ratios tool helps you state clearly what each figure measures.
Learning to challenge a claim is easier when someone challenges you back, which is how online one-to-one Economics tuition can help.