An evaluation earns marks when each claim points to evidence in the question, states the condition it needs, and says where it stops. “I think” sentences do none of the three.
This page belongs to the SPM Economics learning guide. For the lesson-level version of the same idea, see evidence-based economic answers.
What does this look like for you?
You wrote, “The bakery should not raise its price because customers will be unhappy.” The feedback says “opinion”. You feel you gave a reason, so the comment is puzzling.
The reason you gave, unhappy customers, is a feeling that cannot be checked against any number in the question.
What usually causes it?
- Evidence is missing: nothing in the sentence points to a figure or a stated fact.
- The condition is missing: the sentence claims one outcome as if it were certain.
- The limit is missing: the sentence never says when the claim would fail.
- A word of judgement replaces a reason: good, bad, unfair, wasteful.
A worked example
A fictional bakery sells a cake at RM4 and sells 200 a day. It considers a price of RM5.
| Quantity sold at RM5 | Revenue | Compare with RM800 |
|---|---|---|
| 200 | RM1 000 | Higher |
| 170 | RM850 | Higher |
| 160 | RM800 | Equal |
| 150 | RM750 | Lower |
The current revenue is 4 × 200 = RM800. At RM5, revenue is at least RM800 if the bakery sells 160 or more cakes, because 800 ÷ 5 = 160. That is a fall of no more than 20%, since 40 is 20% of 200.
An opinion-style sentence: “The bakery should not raise the price, because customers will be unhappy.”
A supported sentence: “Revenue rises if sales fall by less than 20%, since RM5 × 160 = RM800. Whether they fall by more than that depends on how readily customers switch to other cakes, which the question does not state.”
The second sentence has a claim, evidence (the calculation), a condition (less than 20%) and a limit (the missing switching information).
A four-part frame
- Claim: what you say will happen.
- Evidence: a figure, table entry or stated fact.
- Condition: what must hold for the claim to be true.
- Limit: what the information does not tell you.
Write one sentence per part. The frame gives you a checklist when you review a draft. For causal chains, see the companion page on writing an Economics explanation instead of describing a picture.
What can I do this week?
Take three old evaluation sentences. For each, underline the evidence and circle the condition. If either is missing, rewrite the sentence using the frame. Put any sentence that still fails in your mistake log with the missing part named.
Use the supply-demand diagram reasoning explorer to check the direction of any curve shift you rely on as evidence.
When might one-to-one tuition help?
If you cannot tell which part of your sentence is missing, a teacher reading your draft can name it in a sentence, such as “the condition is absent here”. In a one-to-one lesson the teacher reads your actual wording and points to the gap straight away.
See online one-to-one Economics tuition for how a lesson works, and the one-hour trial class (from RM50) for a first taught lesson.