1. Recognising an argument and its structure

An argument is not simply a disagreement or a collection of facts. It is a structure in which one or more statements, called premises, are presented as reasons for accepting another statement, called the conclusion. For example: 'Every eligible applicant who submitted the form before the deadline was admitted. Rani was an eligible applicant and submitted before the deadline. Therefore, Rani was admitted.' The first two statements support the third.

Words such as because, since and given that often introduce premises. Therefore, hence, consequently and thus often introduce conclusions. These are clues rather than fixed rules: 'since' may refer to time, and a conclusion may appear at the beginning or in the middle of a passage. Identify the statement that the author wants the reader to accept, then ask which statements provide support for it.

Separate arguments from descriptions and explanations. A description reports circumstances without necessarily supporting a conclusion. An explanation ordinarily takes an event as established and accounts for why it happened. An argument tries to establish that a claim should be accepted. A passage may combine all three, so isolate the reasoning relevant to the question.

Main conclusion: the ultimate claim supported by the passage.
Intermediate conclusion: a claim supported by earlier premises that also supports a further conclusion.
Background statement: contextual information that need not function as evidence.

2. Deductive validity, inductive strength and conditional reasoning

A deductive argument claims that its conclusion follows necessarily. It is valid when no possible situation makes all its premises true and its conclusion false. A sound argument is both valid and based on true premises. In a reasoning question that directs candidates to accept the statements as true, test the logical relationship rather than correcting the premises using real-world knowledge.

An inductive argument offers probable rather than conclusive support. Surveys, forecasts and generalisations usually involve induction. Their strength depends on the quality, representativeness and quantity of evidence. A survey of customers leaving an expensive restaurant may describe that restaurant's customers, but it provides weak support for a claim about the food preferences of an entire district.

Conditional reasoning is especially important. 'If P, then Q' makes P sufficient for Q and Q necessary for P. From P, infer Q; from not-Q, infer not-P. Neither Q alone nor not-P alone settles the other condition. 'Only registered candidates may enter' means entry requires registration; it does not guarantee that every registered candidate will enter.

Watch quantifiers and scope. 'Some' means at least one and does not mean 'some but not all'. 'Most' does not mean 'all'. A conclusion about every village cannot normally follow from evidence about selected villages unless the passage supplies a justified connecting principle.

Valid: If P, then Q; P; therefore Q. This is modus ponens.
Valid: If P, then Q; not-Q; therefore not-P. This is modus tollens.
Invalid: If P, then Q; Q; therefore P. This affirms the consequent.
Invalid: If P, then Q; not-P; therefore not-Q. This denies the antecedent.

Argument-solving sequence

1. Identify the question type.
2. Locate the main conclusion.
3. Separate premises from background.
4. Identify the inference or missing link.
5. Apply the appropriate logical test.
6. Compare options for relevance, scope and certainty.

3. Conclusions, assumptions, strengthening and weakening

A conclusion question asks what follows from the supplied statements. Match the certainty demanded by the question: 'must follow' requires necessity, whereas 'most reasonably inferred' permits a carefully supported inference. An attractive option may introduce an entirely new claim, reverse a relationship, or turn a limited observation into a universal rule.

An assumption bridges a gap between the stated evidence and the conclusion. Consider: 'The district should shift applications online because this will make the service accessible to all residents.' This relies on intended users having an effective way to use the online service, directly or through assistance. It does not necessarily require every resident to own a smartphone.

For a necessary-assumption question, use the negation test: negate the proposed assumption and ask whether the argument loses an essential support. Negation must be precise. The negation of 'all applicants have internet access' is 'at least one applicant lacks internet access', not 'no applicant has internet access'. A sufficient assumption is different: adding it makes the conclusion follow, although the argument may not require that exact statement.

A strengthening statement increases support for the conclusion; a weakening statement reduces it. Neither must prove or disprove the conclusion completely. The best option usually addresses the missing connection, a competing explanation, the reliability of evidence or the feasibility of a proposed measure. Merely repeating a premise adds little.

Conclusion: what is established or most reasonably supported?
Assumption: what unstated link does the reasoning require?
Strengthen or weaken: which new fact changes the support most directly?
Evaluate: which question could produce answers that substantially alter the assessment?

Matching the question to the logical test
Question type	Core test	Common trap
Must-follow conclusion	Can the premises be true while the option is false?	Choosing a plausible but non-necessary claim
Necessary assumption	Does negating the option remove essential support?	Choosing a helpful but unnecessary statement
Strengthen	Does the option improve the premise–conclusion connection?	Repeating background information
Weaken	Does the option undermine evidence or the connecting link?	Disagreeing with the objective rather than the argument
Evaluate	Would contrasting answers change the argument's credibility?	Asking about an issue with no bearing on the conclusion

4. Causal claims, policy arguments and fallacies

Causal arguments infer that one factor produces another. Correlation alone does not establish causation. If districts with more hospitals report more illness, illness may have prompted hospital expansion; larger populations may explain both; or better diagnosis may increase recorded cases. Examine reverse causation, common causes, selection effects and measurement differences before accepting the claimed mechanism.

A before-and-after comparison is also vulnerable. Suppose accidents decline after cameras are installed. Better road design, reduced traffic or changed reporting could contribute. Evidence from comparable untreated locations, consistent measurement and a plausible mechanism can strengthen the argument. Such evidence improves causal confidence but should not automatically be treated as definitive proof.

Policy arguments connect a problem, an intervention and an intended outcome. Test whether the measure addresses the identified cause, can be implemented, and creates relevant costs or unintended effects. Do not reject an argument merely because its policy objective differs from your preferences. Relevance to the stated objective matters more than ideological agreement.

Common fallacies include attacking the speaker instead of the reasoning, treating two options as the only possibilities, generalising from an unrepresentative sample, and assuming the conclusion within the premises. Appeals to expertise are not inherently fallacious; their value depends on relevant competence and evidence. Popularity, however, cannot by itself establish that a factual claim is true.

Equivocation: shifting the meaning of a key word during the argument.
Composition: assuming that what is true of each part must be true of the whole.
Division: assuming that what is true of the whole must be true of every part.
Straw man: replacing the actual position with an easier claim to attack.

5. An exam-oriented solving method

Read the question stem first to identify the task. Then compress the passage into 'because premises, therefore conclusion'. Mark restrictions such as only, unless, some, all and probably. Identify the precise gap before comparing options; otherwise, a familiar or persuasive statement can distract you from the reasoning.

Evaluate each option independently. Ask whether it concerns the same population, time period, outcome and degree of certainty as the passage. Eliminate choices that are irrelevant, simply restate the evidence, require unsupported outside assumptions or exaggerate the conclusion. Strong wording is not automatically wrong: it is wrong when the evidence does not justify it.

For validity questions, search for a counterexample in which the premises remain true but the proposed conclusion is false. For causal questions, test alternative explanations. For assumptions, use careful negation. If two answers appear plausible, prefer the one that addresses the exact logical link rather than a broad associated issue.

Practise with an error log containing the conclusion, the missed logical link and the reason each tempting distractor fails. Since CSAT is qualifying but includes negative marking for incorrect objective answers, accuracy and controlled selection are more valuable than indiscriminate attempts.

Use passage evidence first; do not substitute general knowledge for the stated premises.
Distinguish a possibility from a probability, and a probability from a necessity.
Return to difficult items after securing questions you can solve reliably.

Real-world case studies

John Snow and the 1854 London cholera outbreak

John Snow investigated cholera around the Broad Street pump in Soho, London, using the geographical pattern of cases and information about water use. His work illustrates how evidence about exposure can support a causal hypothesis beyond a simple correlation. The pump handle's removal should not alone be treated as decisive proof: the outbreak was already declining. The reasoning lesson is to assess the combined evidence rather than rely on one dramatic event.

Randomised evaluation of remedial education in India

The Balsakhi remedial education programme, implemented by Pratham in Mumbai and Vadodara, was evaluated through randomised assignment. Comparing treatment and comparison groups provided stronger evidence about programme effects than observing improvement among participants alone. Randomisation helps address pre-existing differences on average, but transferring the result to another setting still requires attention to implementation and local conditions.

Previous year questions

No source-linked PYQ is available here yet. Use the practice questions below.

Practice questions

Practice MCQ 1 · Easy

Consider the following passage: A municipal library is currently open only during normal office hours. Many salaried residents cannot visit during these hours. Opening it for two hours in the evening would enable them to use its facilities. Therefore, the municipality should introduce evening opening hours. Which one of the following is the main conclusion of the argument?

A. Many salaried residents cannot visit the library during office hours.
B. The municipality should introduce evening opening hours.
C. The library is currently open only during normal office hours.
D. Evening opening would enable some additional residents to use the library.

Practice MCQ 2 · Easy

Consider the following argument: The district will replace all printed flood warnings with mobile text messages. This will ensure that every household receives a timely warning. Which one of the following is an assumption necessary for the argument?

A. Every household owns more than one mobile phone.
B. Sending text messages is cheaper than printing warnings.
C. Floods occur at the same time every year.
D. Every household has an effective means of receiving the text warning in time, directly or through someone else.

Practice MCQ 3 · Easy

Consider the following argument: If a village has a functioning piped-water system, its residents need not fetch water from a distant source. Residents of Village K do not need to fetch water from a distant source. Therefore, Village K has a functioning piped-water system. What is the principal error in this reasoning?

A. It treats a sufficient condition as though it were necessary.
B. It rejects a conclusion merely because its supporter is unreliable.
C. It assumes that what is true of a whole must be true of each part.
D. It draws a conclusion that directly contradicts an explicit premise.

Practice MCQ 4 · Easy

Consider the following argument: A school proposes supervised bicycle parking. The headteacher argues that this will encourage more students to cycle to school. Which one of the following, if true, most strengthens the argument?

A. The school recently repainted its classrooms.
B. Several teachers prefer walking to cycling.
C. Many students who own bicycles say that fear of bicycle theft is their main reason for not cycling to school.
D. Some students live too far away to cycle to school.

Practice MCQ 5 · Easy

Consider the following statements: Only registered volunteers may enter the relief-material warehouse. Meera entered the warehouse in accordance with this rule. Which one of the following conclusions necessarily follows?

A. Every registered volunteer entered the warehouse.
B. Meera was a registered volunteer.
C. Meera was responsible for distributing relief materials.
D. Registration alone guarantees entry into the warehouse.

Practice MCQ 6 · Moderate

Consider the following passage: Repeated leaks have damaged several records stored in the basement. Repairing the pipes would not eliminate the risk because the basement also floods during heavy rainfall. Thus, the basement is unsuitable for long-term record storage. Since the vacant first-floor room is dry and can accommodate the records without affecting other services, the records should be moved there. What role does the statement 'the basement is unsuitable for long-term record storage' play?

A. It is background information that does not support any conclusion.
B. It is the final recommendation of the passage.
C. It is an objection that the author subsequently rejects.
D. It is an intermediate conclusion supported by earlier statements and used to support the final recommendation.

Practice MCQ 7 · Moderate

Consider the following argument: Farmers who voluntarily attended a soil-management workshop obtained higher average yields than farmers who did not attend. Therefore, attending the workshop caused the higher yields. Which one of the following, if true, most seriously weakens the argument?

A. Workshop participants already had substantially higher average yields before the workshop, and the yield gap did not increase afterwards.
B. The workshop included demonstrations as well as lectures.
C. Some non-participants had heard about soil management through radio programmes.
D. Participants grew more than one variety of crop.

Practice MCQ 8 · Moderate

Accept the following statements as true: Every proposal receiving a green certificate has passed an environmental audit. Some subsidised proposals have not passed an environmental audit. Every proposal receiving a green certificate qualifies for an expedited hearing. Consider the following conclusions: 1. Some subsidised proposals have not received a green certificate. 2. Every proposal qualifying for an expedited hearing has passed an environmental audit. 3. Some proposals that have passed an environmental audit are subsidised. Which of the above necessarily follows?

A. 2 only
B. 1 and 3 only
C. 1 only
D. 1, 2 and 3

Practice MCQ 9 · Moderate

Consider the following argument: After a city introduced a congestion charge, the number of private cars entering its central zone fell by 18%. The charge has therefore reduced total vehicular air pollution across the city. Which one of the following questions is most important for evaluating the argument?

A. Were the congestion-charge notices printed in more than one language?
B. How did emissions from rerouted journeys, replacement modes of transport and travel elsewhere in the city change?
C. Did every private car owner consider the charge fair?
D. Were the central-zone roads built before the outer-city roads?

Practice MCQ 10 · Moderate

Consider the following argument: The automated meter-reading proposal will reduce billing errors and will not increase the utility's annual operating expenditure. Therefore, the utility should adopt it. Which one of the following principles, if accepted, is sufficient to justify the conclusion?

A. Any proposal adopted by the utility should reduce billing errors.
B. Any proposal that increases annual operating expenditure should be rejected.
C. A proposal that reduces billing errors should be considered for a pilot study.
D. The utility should adopt any proposal that reduces billing errors without increasing annual operating expenditure.

Practice MCQ 11 · Difficult

A committee applies the following rules without exception: • Every affordable project that has been independently audited is shortlisted. • Every shortlisted project is recommended if it either requires no displacement or has a certified rehabilitation plan. • A rehabilitation plan is certified only if it has been independently reviewed. • No project located in a drought-prone zone is recommended unless it has water clearance. Project K is affordable, has been independently audited, requires displacement, lies in a drought-prone zone and does not have water clearance. Consider the following conclusions: 1. Project K is shortlisted but is not recommended. 2. Project K does not have a certified rehabilitation plan. 3. Project K's rehabilitation plan has not been independently reviewed. Which of the above necessarily follows?

A. 1 and 2 only
B. 1 only
C. 2 and 3 only
D. 1, 2 and 3

Practice MCQ 12 · Difficult

A training agency classifies participants into two categories before training. It reports the following results: Before a new teaching method: 90 of 100 participants in the better-prepared category completed the course, while 360 of 900 participants in the less-prepared category completed it. After the new method: 720 of 900 participants in the better-prepared category completed the course, while 30 of 100 participants in the less-prepared category completed it. The director argues: 'The overall completion rate rose after the change; therefore, the new method improved participants' chances of completion.' Which one of the following is the most defensible assessment?

A. The argument is conclusive because the total number of participants was unchanged.
B. The overall completion rate fell, although it rose within each category.
C. The overall completion rate rose, but it fell within both categories; the changed participant composition undermines the claimed causal inference.
D. The figures prove that the new method caused a fall in completion probability for every individual participant.

Practice MCQ 13 · Difficult

In a large trial, households were randomly assigned either to receive monthly electricity reports or to receive no reports. Each report combined energy-saving advice with a ranking comparing the household's consumption with that of its neighbours. The groups experienced the same tariffs and weather, and there were no systematic differences in other interventions. Metered grid-electricity use fell by 8% in the report group relative to the control group. The study did not measure generator fuel use, and no group received advice without rankings. An official makes three claims: 1. The report package reduced average grid-electricity use in the trial. 2. Neighbour rankings, rather than advice alone, were necessary for the reduction. 3. The report package reduced households' total energy-related carbon emissions. Which one of the following best assesses these claims?

A. All three claims are supported because random assignment identifies every mechanism through which an intervention operates.
B. Claim 1 is supported, but claims 2 and 3 are not established by the evidence provided.
C. Claims 1 and 2 are supported, but claim 3 is disproved by the absence of generator-fuel measurements.
D. None is supported because unmeasured generator use prevents any inference about metered grid-electricity use.

Practice MCQ 14 · Difficult

An authority inspected all 1,000 pumps in a district in each of two years. Its old test, used in Year 1, flagged exactly 80% of actually faulty pumps and exactly 10% of non-faulty pumps. Its new test, used in Year 2, flagged exactly 90% of actually faulty pumps and exactly 20% of non-faulty pumps. These percentages applied exactly to the pumps inspected in the respective years. The old test flagged 240 pumps; the new test flagged 270. An official argues that the proportion of actually faulty pumps increased because the proportion flagged increased. Which one of the following correctly evaluates the argument?

A. It is correct: the actual fault rate rose from 24% to 27%.
B. It is incorrect: the actual fault rate remained at 20% in both years.
C. The actual fault rates cannot be calculated even with the stated detection and false-positive rates.
D. It is incorrect: the actual fault rate fell from 20% to 10%, despite the rise in the proportion flagged.

Practice MCQ 15 · Difficult

Consider the following argument about a non-empty group of grant recipients: More than half passed the financial audit. More than half passed the social audit. No recipient who failed the disclosure requirement passed both audits. Therefore, more than half of all recipients satisfied the disclosure requirement. For this question, every recipient either satisfied or failed the disclosure requirement. Which one of the following correctly identifies both what the original premises establish and an additional premise sufficient to establish the stated conclusion?

A. At least one recipient satisfied disclosure; adding that every recipient who passed the financial audit also passed the social audit would establish the majority conclusion.
B. No recipient is necessarily shown to have satisfied disclosure; adding that equal numbers passed the two audits would establish the majority conclusion.
C. A majority necessarily satisfied disclosure; no additional premise is needed.
D. At least one recipient satisfied disclosure; adding that every recipient who satisfied disclosure passed both audits would establish the majority conclusion.

Arguments