Markscheme Guide: Explain vs Evaluate in IB
If you know the content but lose marks on evaluate questions, the problem may be the command term rather than your memory. An explain question asks you to make reasons, causes or relationships clear. An evaluate question asks you to weigh evidence against relevant criteria and reach a justified judgement.
That difference is what the markscheme is designed to reward. This guide explains how to recognise both demands, what evaluation must contain, how to use a markscheme effectively, and how to practise producing judgement rather than simply adding more content.
What does “explain” mean in an IB question?
The IB command term explain means to give a detailed account, including reasons or causes. You must show how or why something happens, rather than merely naming a fact or describing a sequence.
A strong explanation normally forms a clear chain:
Cause or factor → mechanism → effect or consequence
For example, in Economics, explaining why an increase in interest rates may reduce consumption requires more than stating that consumption falls. You would connect the higher cost of borrowing and greater incentive to save with less disposable income available for spending, then link this to reduced consumption.
In History, explaining the significance of a development means connecting it to its effects rather than listing what happened. In Biology, explaining a process requires the relevant sequence and relationships between its stages. The content differs by subject, but the central requirement is the same: make the causal or logical relationship visible.
An explain response will usually need:
- Accurate subject knowledge.
- A direct answer to the specific question.
- Clear reasons, causes or mechanisms.
- Links between stages of the reasoning.
- Relevant evidence, data, examples or terminology where required.
An explanation can be complete without weighing alternatives. You do not automatically need a balanced argument or final overall judgement unless the question asks for one.
What does “evaluate” mean in an IB question?
The IB command term evaluate requires you to assess implications and limitations, make judgements, and use selected criteria to decide how convincing, effective, important, valid or successful something is. The current subject guide and markscheme remain the final authority because expectations vary between subjects.
Evaluation is not simply explanation with extra detail. It changes the purpose of the response:
- Explain: Why or how does this happen?
- Evaluate: How valuable, effective, significant, reliable or convincing is it, and under what conditions?
Possible criteria include effectiveness, cost, scale, reliability, equity, ethical impact, short-term and long-term consequences, validity, feasibility or significance. The appropriate criteria depend on the question and subject.
A useful evaluation paragraph often contains four moves:
- Claim: identify a strength, benefit, argument or reason supporting a position.
- Evidence or explanation: show why the claim is relevant and support it with subject-specific material.
- Limitation or counterpoint: identify a condition, weakness, alternative interpretation or factor that reduces the claim.
- Mini-judgement: explain how much the limitation matters and whether the claim remains persuasive.
The conclusion should decide which arguments or criteria matter most overall.
Why content alone is not enough
Students often lose evaluation marks because they produce accurate knowledge but leave the examiner to make the judgement. A response might state that a policy reduces pollution, increases government expenditure, affects low-income households and changes firm behaviour. These points may all be correct, but they do not show which consequence matters most or whether the policy is effective overall.
The examiner needs to see how factors compare. Does the answer change in the short term or long term? Does it depend on implementation, scale or context? Is one criterion more important than the others?
Evaluation is the point at which you answer the question, not merely demonstrate that you revised the topic. A markscheme may credit knowledge and analysis, but the highest levels normally require a judgement that is explicit and convincingly supported.
Explain versus evaluate: key differences
| Feature | Explain | Evaluate |
|---|---|---|
| Main task | Show why or how something happens | Judge its value, success, importance or validity |
| Reasoning | Usually one clear causal or logical chain | Weigh competing factors, strengths and limitations |
| Evidence | Supports the explanation | Supports comparison and judgement |
| Criteria | Not always required | Usually necessary, even if stated briefly |
| Balance | Not automatically required | Relevant counterpoints or limitations are expected |
| Ending | May link back to the question | Should normally include a clear overall judgement |
This is a general guide, not a universal mark allocation. IB assessment differs between subjects, levels and question types. Some subjects use short-answer marking points, while others use levels of response, markbands or criteria. Do not apply a rigid formula without checking the specific question and markscheme.
What the markscheme is looking for
A markscheme is a scoring guide for examiners. It may contain acceptable answers, marking points, method marks, follow-through instructions, level descriptors or notes about response quality. It is not necessarily a model answer that must be copied word for word.
For an evaluate question, look for three layers of demand:
Knowledge and application
You must understand the relevant content and use it in the context of the question. Precise material connected to a case, source, data, extract or wording is more useful than a generic textbook paragraph.
Analysis or reasoning
You must show relationships between evidence and outcomes. Explain why a strength matters, how a limitation affects the argument, or why one consequence may be more significant than another.
Evaluation and judgement
You must weigh the evidence and reach a defensible decision. This may involve conditions, priorities, assumptions, time frames or comparisons. A conclusion that merely repeats the introduction is weaker than one that explains what was decisive.
In quantitative subjects, a markscheme may separate method and accuracy marks. In essay-based or criterion-based components, evaluation is often judged through the quality of the whole argument rather than a fixed number of ticks. The command term is consistent, but the evidence expected differs between Mathematics, Sciences, Economics, History, Psychology and MYP subjects.
How to write a real judgement
A judgement is not the same as saying “in my opinion”. In IB work, it should be based on evidence and a stated or clearly implied standard.
A weak conclusion says:
Overall, there are advantages and disadvantages, so the answer depends on the situation.
This avoids deciding. It does not identify which factors matter most or explain what situation would change the answer.
A stronger conclusion says:
Overall, the policy is likely to be effective when the priority is reducing pollution over the long term, because its behavioural effect is more significant than its immediate administrative cost. However, the judgement is weaker where low-income households cannot be protected through compensation.
This gives a decision, identifies the priority behind it, weighs the arguments and states a condition that could change the judgement. The wording does not need to be complicated. The decision does need to be unmistakable.
A practical method for evaluate questions
Read the whole question
Underline the command term, the subject of the judgement and restrictions such as “with reference to”, “in one country”, “using the source” or “in the short term”. These restrictions are part of the task.
Turn the question into a decision
Ask, “What exactly am I being asked to judge?” It may be the effectiveness of a policy, the significance of an event, the reliability of a source, the usefulness of a method or the validity of a claim.
Choose two or three criteria
Do not evaluate everything. Select the standards most relevant to the question. A policy might be judged by effectiveness, equity and feasibility. A scientific method might be judged by validity, reliability and limitations. A historical interpretation might be judged by evidence, context and explanatory power.
Build pressure into each paragraph
Do not write one paragraph for an advantage and another for a disadvantage without comparison. Show the advantage, support it, test it and decide how much weight it deserves. This places evaluation inside the argument rather than leaving all judgement to a rushed conclusion.
Use explicit weighing language
Phrases such as however, although, this is significant because, the extent of this depends on, more important than, less convincing where, and on balance can make the logic visible. They do not create evaluation by themselves; supporting reasoning is still required.
Finish with a qualified decision
Answer the exact question in the final lines. State what is most convincing or important, why it deserves the greatest weight, and any condition that limits the judgement.
Common mistakes
Listing both sides without weighing them
Balance is not two equal lists. If you present advantages and disadvantages but never compare their importance, you have discussed the material without fully evaluating it.
Summarising instead of judging
A summary tells the examiner what you wrote. A judgement tells the examiner what you decided. Use the conclusion to rank factors and answer the question directly.
Using generic evaluation phrases
“On the other hand” is useful only when it introduces a meaningful limitation. “It depends” is useful only when you explain what it depends on and how that condition changes the answer.
Writing everything you know
Extra content cannot compensate for missing evaluation. More examples may consume time without improving the argument if they do not support or alter the judgement.
Treating evaluate as criticise
Evaluation is not automatically negative. Assess strengths and weaknesses fairly, then decide. A positive judgement can be excellent if it recognises limitations and explains why they do not outweigh the benefits.
Ignoring subject-specific assessment logic
The general meaning of evaluate is consistent, but the evidence expected differs. Science may require experimental limitations; Economics may require diagrams, theory and real-world context; History may require source or historiographical analysis; and an MYP response is assessed against subject criteria and achievement-level descriptors.
How to practise evaluation
When reviewing an answer, do not record only the total mark. Classify each lost mark or weak section as a:
- Knowledge gap.
- Misread command term.
- Missing application or evidence.
- Incomplete chain of reasoning.
- Unclear limitation.
- Unsupported judgement.
- Timing or organisation problem.
Then rewrite one paragraph rather than the entire answer. Add the missing move: a criterion, limitation, comparison or mini-judgement. Targeted repair is more useful than repeatedly writing longer essays.
RevisionDojo’s Question Bank can help you practise command terms across topics. Past paper solutions and markschemes allow you to compare your reasoning with expected responses, while notes and cheatsheets help rebuild content gaps. The Jojo AI Study Partner can identify whether a draft contains a judgement or only explanation, but its feedback is study support, not official IB marking.
Final takeaway
The difference between explain and evaluate is the difference between showing how a claim works and deciding how far that claim should be accepted. An explain answer develops reasons or causes. An evaluate answer uses relevant evidence, tests strengths and limitations against criteria, weighs their importance and reaches a justified conclusion.
When using a markscheme, look beyond the content list. Ask what knowledge was needed, what reasoning had to be visible and where the judgement was earned. RevisionDojo’s Question Bank, markscheme-linked past paper solutions and Jojo AI Study Partner can provide a practical feedback loop for building this habit.
