Case evidence is specific, checkable detail about a named place or event that backs up one step of your explanation. It appears when a question says “with reference to a case study” or “use named examples”, and it can also lift any other explanation.
It builds on the linked process sequence from the previous lesson. The chain gives the reasoning, and the evidence shows that the reasoning really happened somewhere.
What makes evidence appropriate?
Appropriate evidence has four qualities. Check each one before you write it down.
- Specific: a place, a date, a figure or a named feature.
- Relevant: it supports the exact step you are explaining, not just the topic.
- Accurate: you can say where it came from, and you can describe it neutrally.
- Placed: it sits inside the sentence it supports, not in a block at the end.
The evidence and case-study ledger is a good way to store each case with its place, date, source and one figure.
Worked example
The town below is invented for practice, and the figures are invented too. In your own answers, use real cases from your notes and check each fact against its source.
Riverton (invented): a town on a flat floodplain. On 12 June, 62 mm of rain fell in 3 hours. The river rose 2.4 m above its normal level, and 340 homes were affected.
Question: Explain why Riverton flooded on 12 June.
Step 1, the rate. 62 mm in 3 hours is 62 ÷ 3 = 20.67, so about 20.7 mm per hour. Check: 20.7 × 3 = 62.1, which matches 62 within rounding.
Step 2, attach each fact to a step. The rate supports “intense rain”. The 2.4 m rise supports “the channel overtopped”. The 340 homes show the impact on the floodplain.
Step 3, write it:
Rain fell at about 20.7 mm per hour in Riverton on 12 June, so the ground and drains could not absorb it quickly. Water ran over the surface into the river, which rose 2.4 m above its normal level. Because the town sits on a flat floodplain, the water spread across the low land and affected 340 homes.
Notice that each figure has a job. None of them is there only to look impressive.
The mistake to watch for
Mistaken answer: “Floods happen in lots of places, like Asia, when it rains a lot and rivers overflow.”
“Asia” is a continent, not a case, and “a lot” carries no scale. Nothing here shows the student knows a particular event.
The correction is to name the place and period, give one figure and tie it to a step. For example: In Riverton on 12 June, 62 mm fell in 3 hours, so the river overtopped its banks. If you are unsure of a detail in a real case, choose the detail you can support and leave out the rest.
Check yourself
1. Which sentence is better evidence? (a) “Many towns suffer floods.” (b) “Riverton had 62 mm of rain in 3 hours.”
Show answer
(b). It names a place and gives a figure and a time span. Sentence (a) is true but could apply to any town, so it supports nothing in particular.
2. In another invented event, 45 mm fell in 2 hours. Find the rate in mm per hour, and say which step of an explanation it supports.
Show answer
45 ÷ 2 = 22.5 mm per hour. It supports the step “intense rainfall”. Check: 22.5 × 2 = 45.
3. A student writes a case fact in the last line of the answer only. Why does it earn less than it could?
Show answer
It is not tied to any step, so it does not support the reasoning. Moving it inside the sentence it supports shows the marker exactly which link it proves.
Where this leads next
Next, learn how the question wording decides what kind of answer you give in interpreting a command word. Practise the whole chain with evidence in the mixed practice set.
When your case notes feel crowded or you are unsure which facts to keep, our teachers can sort them with you in online one-to-one Geography tuition.