UPSC Mains 2021 Economics Optional Question Papers with Model Answers

All 56 questions of the 2021 Civil Services Main Examination, Economics Paper I and Economics Paper II, with marks and a suggested time per part. Solve each part on paper first, then open the model answer, or send it to answer-writing practice for evaluation.

UPSC Mains 2021 Economics Paper I

Question 1 (50 marks)

Q1(a) · Price Determination and Theories of Distribution · 10 marks≈ 7 min
Marshallian and Walrasian Approaches to Price Determination
Compare and contrast Marshallian and Walrasian approaches of the stability in equilibrium.
हिंदी में प्रश्न
सन्तुलन में स्थिरता के मार्शलियन तथा वालरासियन दृष्टिकोण की तुलना करें एवं अन्तर प्रदर्शित करें।
Practise this question Price Determination and Theories of Distribution notes
Model answer
Paper and question: Paper I, Q1(a)
Approach: Compare the two approaches on the adjusting variable, time period and stability condition, then contrast them in the case where both curves slope the same way.
Both approaches ask whether a disturbed competitive market returns to equilibrium; they differ in what adjusts.
Walrasian stability (Walras, 1874): price adjusts to excess demand, dP/dt = k·E(P). Equilibrium is stable if excess demand falls as price rises (D′(P) less than S′(P)). It describes auction-type markets.
Marshallian stability (Marshall, 1890): quantity adjusts to the gap between demand price and supply price, dQ/dt = k·[Pd(Q) − Ps(Q)]. It is stable if to the right of Q* supply price exceeds demand price (Pd′ less than Ps′). It describes long-period output decisions of producers.
Similarity and contrast: both conditions hold for a downward demand and an upward supply curve; but when both curves slope the same way (a backward-bending labour supply curve, a decreasing-cost industry with external economies, or a Giffen good) the verdicts are opposite: if negatively sloped supply is steeper than demand, equilibrium is Walras-stable but Marshall-unstable, and if flatter, Marshall-stable but Walras-unstable.
Diagram: (P, Q) space with a downward demand curve and a steeper downward supply curve crossing at E; mark excess supply horizontally above P* and the supply price above demand price vertically to the left of Q*.
Walras suits markets with fast-moving prices, Marshall those where output responds slowly.
Q1(b) · Welfare Economics · 10 marks≈ 7 min
Amartya Sen: Social Choice, Welfare and Capabilities
Using generalised Lorenz dominance show that lower inequality represents a higher social welfare state.
हिंदी में प्रश्न
सामान्यीकृत लारेंज प्रभुत्व का प्रयोग करते हुए दर्शाइए कि निम्नतर असमानता एक उच्चतर सामाजिक कल्याण की स्थिति को व्यक्त करती है।
Practise this question Welfare Economics notes
Model answer
Paper and question: Paper I, Q1(b)
Approach: Define the Lorenz and generalised Lorenz curves, state Shorrocks' theorem linking GL dominance to welfare for all increasing, S-concave welfare functions, and show with a numerical example that lower inequality at the same mean gives higher welfare.
The Lorenz curve L(p) plots the cumulative share of income received by the poorest fraction p of the population. The generalised Lorenz curve (Shorrocks, 1983) scales it by mean income: GL(p) = μ·L(p), so it reflects both the size and the distribution of income.
Theorem: Atkinson (1970) showed that, for equal means, Lorenz dominance implies higher welfare under every additive welfare function with increasing, concave u. Shorrocks (1983) showed that x generalised-Lorenz-dominates y if and only if W(x) ≥ W(y) for all increasing, S-concave welfare functions, even with different means.
Q1(c) · Theories of Employment, Income and Interest · 10 marks≈ 7 min
Investment, Business Cycles and Aggregate Demand–Supply
Examine the relationship between business cycle and changes in autonomous expenditure.
हिंदी में प्रश्न
व्यापार चक्र एवं स्वायत्त-व्यय में परिवर्तन के मध्य स्थित सम्बन्ध का परीक्षण कीजिए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q1(c)
Approach: Explain how shocks to autonomous spending (especially investment) start cycles through the multiplier, how the accelerator turns them into cumulative swings (Samuelson, Hicks), and how ceilings and floors produce turning points.
Keynesian theory explains business cycles mainly by fluctuations in autonomous expenditure, especially investment, which depends on volatile expectations ('animal spirits', Keynes, 1936), as well as exports and government spending.
Multiplier: a rise in autonomous spending ΔA raises income by ΔA/(1 − c); a fall reduces it by a multiple. This explains the amplitude of expansions and contractions.
Multiplier-accelerator interaction (Samuelson, 1939): induced investment depends on the change in income, Iₜ = v(Yₜ₋₁ − Yₜ₋₂), and consumption on past income, Cₜ = cYₜ₋₁. A once-for-all rise in autonomous spending then produces oscillations whose nature (damped, explosive, regular) depends on c and v.
Hicks (A Contribution to the Theory of the Trade Cycle, 1950): growing autonomous investment sets the trend; full-employment ceiling and floor (gross investment cannot be negative) produce turning points.
Diagram: time on the horizontal axis and log output on the vertical; a rising equilibrium path from autonomous investment, a ceiling line above and a floor below, with output cycling between them.
In India, swings in private investment and the 2020 collapse in spending show this link.
Q1(d) · Public Finance · 10 marks≈ 7 min
Public Borrowing, Crowding Out and Limits to Debt
Does government borrowing always crowd out the private investment? Illustrate.
हिंदी में प्रश्न
क्या सरकारी-उधार निजी-निवेश के होने को सदैव रोकता है? उदाहरण देकर समझाइए।
Practise this question Public Finance notes
Model answer
Paper and question: Paper I, Q1(d)
Approach: Answer 'no': show with IS-LM that crowding out depends on the slopes of LM and IS and on the state of the economy, and mention crowding in.
No. Government borrowing crowds out private investment only when it raises interest rates and resources are fully used; the extent depends on the IS-LM slopes.
Full crowding out: with a vertical LM curve (classical case, money demand insensitive to interest) or at full employment, a fiscal expansion only raises r, and private investment falls by the full amount of the extra spending.
No crowding out: in a liquidity trap (horizontal LM, as Keynes described for a depression), borrowing does not raise r, so income rises by the full multiplier. The same holds if the central bank accommodates by expanding money supply, or if investment is interest-inelastic (vertical IS).
Crowding in: with unemployed resources, public investment in infrastructure raises demand and the productivity of private capital, so private investment can rise through the accelerator; India's capex push after 2021 rested on this argument.
Diagram: IS shifts right from IS1 to IS2; with an upward-sloping LM, r rises and Y rises less than the horizontal shift (partial crowding out); with a horizontal LM the full shift; with a vertical LM no change in Y.
Hence crowding out is a possibility, not a law.
Q1(e) · Theories of Employment, Income and Interest · 10 marks≈ 7 min
IS-LM Model and the Neo-classical Synthesis
The slope of the IS schedule will become steeper if the government reduces the rate of proportional tax but will not change at all if the government reduces the level of a lump sum tax. True or false? Explain.
हिंदी में प्रश्न
यदि सरकार अनुपाती कर की दर को घटा दे तो IS वक्र अधिक खड़ी ढाल वाला हो जायेगा किन्तु यदि एकमुश्त कर का स्तर घटाया जाये तो IS वक्र का ढाल परिवर्तित नहीं होगा। सत्य अथवा असत्य? समझाइए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q1(e)
Approach: Derive the IS slope −[1 − c(1 − t)]/b; show that a lower tax rate makes IS flatter (so the first claim is false) while a lump-sum tax cut only shifts IS (second claim true).
Answer: the statement is false in its first part and true in its second.
Final answer: the statement is false in its first part and true in its second.

Question 2 (50 marks)

Q2(a) · Market Structures · 15 marks≈ 11 min
Duopoly Models: Cournot, Bertrand, Stackelberg and Edgeworth
Explain the differences between Cournot model of duopoly with similar product and differentiated product.
हिंदी में प्रश्न
कुर्नो के सजातीय उत्पाद द्वयाधिकार मॉडल तथा विभेदीकृत-उत्पाद द्वयाधिकार मॉडल की भिन्नताओं की व्याख्या कीजिए।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q2(a)
Approach: Set out Cournot with a homogeneous product (one market price) and with differentiated products (each firm's own demand depends on both outputs), compare reaction functions, equilibrium, prices and profits, with a diagram.
In the Cournot model (1838) each duopolist chooses its output assuming the rival's output is fixed, and equilibrium is where the reaction functions intersect (a Nash equilibrium in quantities). The nature of the product changes the demand each firm faces.
Similar (homogeneous) product: buyers regard the outputs as perfect substitutes, so there is one market price P = a − b(q₁ + q₂). Each unit of the rival's output lowers a firm's price as much as its own unit does. Reaction functions: qᵢ = (a − c)/2b − qⱼ/2, and equilibrium output is (a − c)/3b each, with a single price.
Differentiated product: each firm has its own inverse demand pᵢ = a − bqᵢ − dqⱼ, with d between 0 and b, so the rival's output lowers a firm's price less than its own does. Reaction functions become qᵢ = (a − c)/2b − (d/2b)qⱼ, and equilibrium output qᵢ = (a − c)/(2b + d) exceeds (a − c)/3b; the two prices can differ.
Differences: (i) one price versus two; (ii) interdependence, measured by d/b, is full under homogeneity and partial under differentiation; (iii) differentiated firms retain more market power; (iv) as d tends to 0 each firm becomes a monopolist, and as d tends to b the homogeneous case returns.
Diagram: q₁ and q₂ axes; reaction functions for the homogeneous case cross at C; with differentiation the reaction functions rotate outward (each responds less to the rival) and cross at C′ further from the origin.
Differentiation thus softens competition, which is why firms invest in branding.
Q2(b) · Market Structures · 15 marks≈ 11 min
Oligopoly: Kinked Demand, Collusion, Price Leadership and Game Theory
What type of conjecture is involved in the existence of kinked demand curve? Do you think that kinked demand curve model is a price determination model in an oligopoly market? Justify your answer.
हिंदी में प्रश्न
व्याकुंचित माँग वक्र में किस प्रकार का अनुमान शामिल है? आपके अनुसार क्या व्याकुंचित माँग वक्र मॉडल अल्पाधिकार बाजार में एक कीमत-निर्धारण का मॉडल है? अपने उत्तर को उचित सिद्ध कीजिए।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q2(b)
Approach: Identify the asymmetric conjecture behind the kink, then argue that the model explains price rigidity but not price determination, giving reasons and the diagram.
Conjecture: the kinked demand curve (Sweezy, 1939; also Hall and Hitch, 1939) rests on an asymmetric conjectural variation: each firm expects rivals to match any price cut (to protect their market share) but to ignore any price rise (to win its customers). Hence the conjectural variation is positive for price reductions and zero for price increases.
Result: demand is elastic above the prevailing price and inelastic below it, giving a kink at the current price and a vertical gap in the MR curve; marginal cost can vary within the gap without changing price or output.
Is it a price determination model? No. (i) It takes the prevailing price P* as given and explains why it tends to stay there, not how P* was reached; the kink sits wherever the price happens to be. (ii) It is thus a theory of price rigidity, not of price formation. (iii) It cannot predict the new price after a shock that pushes MC outside the gap.
Diagram: demand curve with a kink K at P*; the MR gap below K; MC₁ and MC₂ within the gap giving the same P*; label P* as 'given', with no mechanism shown for its determination.
Assessment: the price may originally be set by collusion, price leadership or full-cost pricing (Hall and Hitch); the kinked demand model then explains its stability. Stigler's (1947) evidence that price rises are often followed by rivals further weakens it. It is best treated as a complement to price-determination models, not a substitute.
Q2(c) · Price Determination and Theories of Distribution · 20 marks≈ 14 min
Ricardian Theory of Distribution
Examine how profit, wage and rent in Ricardian system move differently with the movements in level of income.
हिंदी में प्रश्न
परीक्षण कीजिए कि रिकार्डो की व्यवस्था में लाभ, मजदूरी एवं लगान, आय के स्तर की गतिशीलता के साथ किस प्रकार भिन्न भिन्न तरह से गतिशील होते हैं।
Practise this question Price Determination and Theories of Distribution notes
Model answer
Paper and question: Paper I, Q2(c)
Approach: Set out Ricardo's corn model, write rent, wages and profit as functions of employment, then trace each as accumulation raises income, using the marginal-product diagram.
David Ricardo, in On the Principles of Political Economy and Taxation (1817), held that the principal problem of political economy is to determine the laws that regulate distribution among landlords, capitalists and labourers.
Assumptions: one good (corn); land of varying fertility in fixed supply, so the marginal product of labour falls; a subsistence natural wage w fixed by Malthusian population adjustment; capital as a wage fund; perfect competition.
Shares: with output Y = f(N), f′ positive and f″ negative: rent R = f(N) − N·f′(N), the surplus on intra-marginal land (differential rent); wages W = w·N; profit Π = N·[f′(N) − w], the residual on the marginal land, which pays no rent; the rate of profit r = (f′(N) − w)/w.
Movement with income: as capital accumulates, employment N and total output (income) rise and cultivation extends to poorer land.
(i) Rent rises absolutely and as a share, as the gap between average and marginal product widens. (ii) The wage rate stays at subsistence in the long run (a higher market wage lasts only until population catches up), so the wage bill rises with N while the real wage is constant. (iii) The rate of profit falls steadily as f′(N) falls towards w; total profits first rise and then fall, since dΠ/dN = f′ − w + N·f″ turns negative.
Diagram: N on the horizontal axis and output per worker on the vertical; falling AP and MP curves and a horizontal wage line w; at N1, wages are the rectangle under w, profit the rectangle between MP and w, rent the area between AP and MP; moving to N2 enlarges rent, shrinks profit, and at Ns where MP = w profit vanishes.
Implication: landlords' interests oppose those of the rest of society; rent squeezes profit, accumulation slows and the economy approaches the stationary state, so Ricardo urged repeal of the Corn Laws (achieved in 1846).
Assessment: technical progress and cheap imports postponed diminishing returns, so profits did not fall as predicted; still, this is the first macro theory of distribution.

Question 3 (50 marks)

Q3(a) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
New Classical and New Keynesian Macroeconomics
Show that differences in underlying expectation lead to differences in Keynesian and classical aggregate supply curve.
हिंदी में प्रश्न
दर्शाइए कि निहित प्रत्याशा (अन्डरलाइंग एक्सपैक्टेशन) में भेद, कीन्सियन एवं क्लासिकल समग्र पूर्तिवक्र में भेद उत्पन्न करते हैं।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q3(a)
Approach: Show that labour supply depends on the expected real wage W/Pᵉ and demand on the actual real wage W/P; with fixed or adaptive expectations a rise in P raises employment (upward or Keynesian AS), while with correct expectations (Pᵉ = P) employment is unchanged (vertical classical AS).
The shape of the aggregate supply curve depends on how workers form expectations of the price level, because they bargain over money wages while caring about real wages.
Labour market: firms know the actual price, so labour demand depends on the actual real wage: Nᵈ = f(W/P). Workers do not know the current price level when supplying labour, so supply depends on the expected real wage: Nˢ = g(W/Pᵉ), which can be written in terms of W/P as g[(W/P)·(P/Pᵉ)].
Classical AS (correct expectations): if workers anticipate prices correctly (Pᵉ = P, perfect foresight or rational expectations without surprises), a rise in P raises money wages in proportion; the real wage and employment are unchanged, and output stays at the full-employment level. AS is vertical.
Keynesian AS (expectations lag): if Pᵉ is fixed or adjusts slowly (adaptive expectations, money illusion), a rise in P is not fully perceived; workers accept money wages that rise less than prices, the actual real wage falls, firms hire more and output rises. AS slopes upward. In the extreme case of a rigid money wage and unused capacity (Keynes), AS is horizontal up to full employment.
Diagram: upper panel, labour market with Nᵈ(W/P) and Nˢ; a rise in P with Pᵉ fixed shifts Nˢ (drawn in W/P) to the right, raising employment from N₁ to N₂; lower panel, (Y, P) space with a vertical AS (Pᵉ = P) and an upward AS (Pᵉ given), crossing at the expected price level.
Q3(b) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
Theories of Interest Rate Determination and the Term Structure
Apply the theory of liquidity preference to explain why an increase in money supply lowers the interest rate. What does this explanation assume about the price level?
हिंदी में प्रश्न
तरलता-पसन्दगी सिद्धान्त का प्रयोग करते हुए व्याख्या कीजिए कि मुद्रा-पूर्ति में वृद्धि ब्याज-दर को क्यों कम कर देती है। इस व्याख्या में कीमत-स्तर के प्रति क्या धारणा बनायी गयी है?
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q3(b)
Approach: Explain money demand and supply in the liquidity preference framework, trace the bond-market mechanism by which more money lowers the rate, show the diagram, and state the fixed-price-level assumption and what happens if prices rise.
In Keynes' liquidity preference theory (1936), money demand L(Y, r) rises with income (transactions) and falls with the interest rate (speculative), while the central bank fixes a vertical money supply.
Mechanism: suppose the central bank raises the money supply from M₁ to M₂ through open market purchases. At the old interest rate r₁, people hold more money than they wish to. They try to convert the excess into interest-bearing assets by buying bonds. Greater demand for bonds raises bond prices, and since bond yields move inversely with prices, the interest rate falls. As r falls, the opportunity cost of holding money declines and the quantity of money demanded rises, until at r₂ people are willing to hold the larger stock.
Diagram: interest rate on the vertical and real money balances on the horizontal axis; a downward-sloping money demand curve L(Y); vertical supply lines at M₁/P and M₂/P; equilibrium moves from E₁ (r₁) to E₂ (r₂) as the supply line shifts right.
Assumption about the price level: the explanation assumes the price level is fixed in the short run, so a rise in nominal money is a rise in real money balances M/P. If prices rose in proportion to the money supply (as the classical theory predicts in the long run), real balances would be unchanged, the money supply line would not shift in real terms, and the interest rate would return to its original level; the liquidity effect is therefore a short-run effect.
Q3(c) · Money and Monetary Management · 20 marks≈ 14 min
Keynes and Post-Keynesian Theories of Demand for Money
Explain how the weaknesses of Keynesian speculative demand for money have been identified in Regressive Expectations model.
हिंदी में प्रश्न
कीन्स की मुद्रा की अपेक्षी माँग की कमियाँ प्रतिगामी प्रत्याशा मॉडल में किस प्रकार चिह्नित की गई है, व्याख्या कीजिए।
Practise this question Money and Monetary Management notes
Model answer
Paper and question: Paper I, Q3(c)
Approach: Set out Keynes' speculative demand as a regressive-expectations model (normal rate, critical rate rc = rn/(1 + rn), all-or-nothing choice, aggregation), then identify its weaknesses and Tobin's portfolio-balance answer.
Keynes' speculative demand for money (General Theory, 1936) was formalised by Tobin ('Liquidity Preference as Behavior Towards Risk', 1958) as a regressive expectations model: each wealth holder has a firm idea of the 'normal' interest rate rₙ and expects the actual rate to move back towards it.
Model: for a perpetual bond (consol) the price is 1/r. If the expected rate is rₙ, the expected capital gain per rupee is r/rₙ − 1, so the expected total return on bonds is r + r/rₙ − 1. Bonds are preferred to money if this is positive, i.e. if r exceeds the critical rate r_c = rₙ/(1 + rₙ). Above r_c the individual holds all wealth in bonds; below it, all in money.
Aggregate demand: since different individuals hold different normal rates, the aggregate speculative demand is a smooth, downward-sloping function of the interest rate; if everyone holds the same normal rate and r is very low, demand becomes perfectly elastic: the liquidity trap.
Weaknesses identified: (i) all-or-nothing portfolios: each individual holds either only bonds or only money, which contradicts the observed diversification of portfolios; (ii) the downward slope of aggregate demand depends entirely on differences of opinion about the normal rate, not on individual behaviour; (iii) the normal rate is taken as given; if expectations adapt to actual rates, as they will over time, the speculative demand disappears in the long run and there is no stable money-demand relation; (iv) expected returns are treated as certain, ignoring risk; (v) the liquidity trap requires near-unanimity of expectations.

Question 4 (50 marks)

Q4(a) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
New Classical and New Keynesian Macroeconomics
Derive short-run aggregate supply curve following Lucas, when expectations are not realised, assuming that labour market clears. What will be its shape when expectations are fulfilled?
हिंदी में प्रश्न
श्रम-बाजार को सन्तुलित मानते हुए, प्रत्याशायें पूर्ण न होने की दशा में, लूकस का अल्पकाल समग्र-पूर्ति वक्र व्युत्पन्न कीजिए। प्रत्याशाएं पूर्ण होने पर इस वक्र का स्वरूप क्या होगा?
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q4(a)
Approach: Set out Lucas's islands model: producers see their own price but not the general price level, solve the signal-extraction problem, aggregate to Y = Yn + β(P − Pᵉ), and show the curve is vertical when P = Pᵉ.
Lucas (1972, 1973) derived an upward-sloping short-run AS in a market-clearing, rational-expectations model from imperfect information.
Assumptions: producers live on separate 'islands' (markets); each observes the price of its own good, pᵢ, instantly, but learns the general price level P only with a lag; all markets clear; producers want to raise output only when their relative price rises.
Signal extraction: the observed price is pᵢ = P + zᵢ, where zᵢ is the relative-price shock. A producer cannot tell whether a rise in pᵢ reflects a relative demand shift (worth responding to) or general inflation (not worth responding to). The best estimate of the relative price is θ(pᵢ − Pᵉ), where θ = σ²z/(σ²z + σ²P) is the share of total price variance due to relative shocks.
Supply of each producer: yᵢ = yn + b·θ(pᵢ − Pᵉ). Averaging over islands, the aggregate supply is Y = Yn + β(P − Pᵉ), with β = bθ.
When expectations are not realised: if P exceeds Pᵉ, producers partly mistake general inflation for higher relative prices, raise output and hire more labour in a clearing labour market; output exceeds Yn. If P falls short of Pᵉ, output falls below Yn. The short-run AS curve, drawn for a given Pᵉ, therefore slopes upward.
Diagram: (Y, P) space; vertical LRAS at Yn; upward SRAS drawn for Pᵉ₁, cutting LRAS at P = Pᵉ₁; a higher expected price shifts SRAS up to Pᵉ₂.
Q4(b) · Money and Monetary Management · 15 marks≈ 11 min
Supply of Money and the Money Multiplier
Describe high powered theory of money supply in brief. State the assumptions made in its construction.
हिंदी में प्रश्न
उच्च-शक्ति मुद्रा-पूर्ति सिद्धान्त का संक्षेप में वर्णन कीजिए। इस सिद्धान्त के निर्माण में प्रयुक्त मान्यताओं को बताइए।
Practise this question Money and Monetary Management notes
Model answer
Paper and question: Paper I, Q4(b)
Approach: Define high-powered money and its sources, derive M = mH with m = (1 + c)/(c + r), explain how changes in H and m change M, and list the assumptions.
The high-powered money (H) theory of money supply, developed by Friedman and Schwartz (1963) and Cagan (1965), explains the money stock as a multiple of the monetary base created by the central bank.
High-powered money: H = C + R, currency with the public plus bank reserves; in India, reserve money (M0), created through RBI's credit to government, banks and the commercial sector and its net foreign assets.
Theory: money supply M = C + D. Dividing by H and using c = C/D and r = R/D gives M = [(1 + c)/(c + r)]·H = mH. Money supply changes if H changes (open market operations, central bank credit, foreign exchange purchases) or if m changes (CRR, the public's currency preference, banks' excess reserves). For example, with c = 0.2 and r = 0.1, m = 4, so a rise of ₹1,000 crore in H raises M by ₹4,000 crore.
Assumptions: (i) H is exogenous, controlled by the central bank; (ii) c and r are stable and predictable behavioural ratios, independent of H; (iii) banks are fully loaned up or hold a stable proportion of excess reserves; (iv) there is enough demand for credit for banks to lend their excess reserves; (v) the public's division of money between currency and deposits does not change with the volume of money; (vi) closed economy, or foreign flows are part of H.
Diagram: an inverted pyramid: a narrow base H (C + R) supporting a wider top M (C + D), with the width ratio m = (1 + c)/(c + r).
Q4(c) · Balance of Payments and Exchange Rates · 20 marks≈ 14 min
Policy Mix: Swan Diagram, Mundell's Assignment and Mundell-Fleming
Do you think that increase in Government spending through borrowing from public accompanied by fall in required reserve ratio generates recession in the economy? Illustrate your answer:
(i) in a closed economy with fixed exchange rate.
(ii) in an open economy with fixed exchange rate and without any capital mobility.
हिंदी में प्रश्न
आपके विचार से क्या सार्वजनिक उधार द्वारा सरकारी व्यय में वृद्धि एवं साथ ही वांछित-आरक्षण-अनुपात कम होने से अर्थव्यवस्था में मंदी की स्थिति उत्पन्न होती है? निम्न परिस्थितियों में समझाइए :
(i) एक बन्द अर्थव्यवस्था में स्थिर विनिमय दर के साथ।
(ii) एक खुली अर्थव्यवस्था में स्थिर विनिमय दर एवं बिना किसी पूंजी-गतिशीलता के साथ।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q4(c)
Approach: Show the combined fiscal and monetary expansion: (i) in a closed economy with IS-LM (both shift right, output rises, no recession); (ii) in an open economy with a fixed rate and no capital mobility (vertical BP): the current account deficit drains reserves and money until output returns to the BP level, again no recession but no lasting gain.
No. A bond-financed rise in government spending is an expansionary fiscal policy, and a cut in the required reserve ratio raises the money multiplier and the money supply, an expansionary monetary policy. Together they do not cause a recession; the question is how much and how long output rises.
(i) Closed economy: the rise in G shifts IS right; borrowing from the public would raise the interest rate and crowd out some private investment, but the lower reserve ratio shifts LM right, offsetting the rise in r. Output rises unambiguously, and by more than with fiscal policy alone; the interest rate may rise, fall or stay the same depending on the relative shifts. (The exchange rate is irrelevant in a closed economy.)
Diagram (i): IS1 to IS2 and LM1 to LM2 in (Y, r) space; the new equilibrium E2 lies to the right of E1, with Y2 well above Y1.
(ii) Open economy, fixed exchange rate, no capital mobility: the BP curve is vertical at the income Y_BP at which the current account balances, since capital flows do not respond to interest rates. The expansion raises income above Y_BP, so imports rise and a current account deficit appears. To hold the peg, the central bank sells foreign exchange, reducing the monetary base; unless it sterilises, the money supply falls and LM shifts left until equilibrium returns to Y_BP, now at a higher interest rate with the larger G (so private investment is crowded out).
Diagram (ii): vertical BP at Y_BP; IS shifts right and LM shifts right, giving a temporary point to the right of BP; LM then shifts left until it cuts the new IS on the BP line at a higher r.
So in neither case does recession result: in a closed economy output rises; in the open economy without capital mobility the output gain is temporary and the lasting effects are a higher interest rate, lower reserves and crowding out. A recession could arise only if reserves are exhausted and a forced devaluation or credit squeeze follows.

Question 5 (50 marks)

Q5(a) · Theories of Growth · 10 marks≈ 7 min
Balanced and Unbalanced Growth: Rosenstein-Rodan, Nurkse and Hirschman
Explain Rosenstein-Rodan's view that economic underdevelopment is the outcome of a massive coordination failure.
हिंदी में प्रश्न
आर्थिक-अविकास एक विशाल समन्वय की असफलता का परिणाम है। रोजेन्स्टीन-रोडां के इस दृष्टिकोण की व्याख्या कीजिए।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q5(a)
Approach: Explain Rosenstein-Rodan's argument: complementarity of demand and indivisibilities mean individually unprofitable investments become profitable together, so underdevelopment is a coordination failure needing a big push.
Paul Rosenstein-Rodan, in 'Problems of Industrialisation of Eastern and South-Eastern Europe' (1943), argued that poor countries stay poor not because profitable opportunities are absent but because investors fail to coordinate.
A single shoe factory cannot sell its output, because its workers spend only a small part of their wages on shoes. If many industries expand together, workers in each become customers of the others, so investments unprofitable alone become profitable together. This complementarity of demand, together with indivisibilities in infrastructure and in the supply of savings, creates pecuniary external economies that no single investor takes into account.
The economy can therefore be stuck in a low-level equilibrium even though a high-level equilibrium exists: a coordination failure. Murphy, Shleifer and Vishny (1989) formalised this as multiple equilibria.
The remedy is a big push: coordinated, large-scale investment, usually planned by the state, in infrastructure and a range of complementary industries. Critics note that open economies can use export markets instead.
Q5(b) · Economic Development · 10 marks≈ 7 min
Measuring Development: Human Development Indices and the Basic Needs Approach
Explain how gender sensitive human development index can be constructed.
हिंदी में प्रश्न
लिंग संवेदनशील मानव विकास सूचकांक किस प्रकार निर्मित किया जा सकता है, व्याख्या कीजिए।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q5(b)
Approach: Show how a gender-sensitive HDI is built: separate female and male indices for each HDI dimension, then either the GDI ratio or the equally-distributed-equivalent penalty; mention the GII.
A gender-sensitive HDI adjusts average human development for disparities between women and men. UNDP's Gender Development Index (GDI) is built in four steps.
Construction: (1) estimate female and male values of each indicator: life expectancy, mean and expected years of schooling, and estimated earned income (derived from wage ratios, labour-force shares and GNI). (2) normalise each using goalposts (life expectancy 22.5–87.5 years for women and 17.5–82.5 for men, reflecting women's biological advantage). (3) compute a female HDI and a male HDI as geometric means of their dimension indices. (4) GDI = HDI_female/HDI_male; a value below 1 shows female disadvantage.
The earlier 1995 method combined female and male indices into an 'equally distributed equivalent' with an aversion parameter ε = 2, penalising the HDI for gender gaps.
Agency is captured separately by the Gender Inequality Index (2010), using maternal mortality, adolescent births, parliamentary seats, secondary education and labour-force participation.
Q5(c) · Balance of Payments and Exchange Rates · 10 marks≈ 7 min
Capital Mobility, Speculation and International Policy Coordination
Show that the economic integration is the pre-requisite to establish covered interest rate parity.
हिंदी में प्रश्न
दर्शाइए कि आच्छादित ब्याज दर समानता स्थापित करने के लिये आर्थिक एकीकरण एक पूर्वापेक्षा है।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q5(c)
Approach: State covered interest parity with the forward premium, derive it from arbitrage, and show why it requires integrated markets (free capital mobility, no controls or default risk, low transaction costs), with evidence.
Covered interest parity (CIP) states that the interest differential between two currencies equals the forward premium: (1 + i) = (1 + i*) × F/S, or approximately i − i* = (F − S)/S, where S is the spot rate, F the forward rate (domestic currency per foreign unit), i the domestic and i* the foreign interest rate.
Derivation: an investor can earn (1 + i) on one rupee at home, or convert it at S, invest abroad at i* and sell the proceeds forward at F, earning (1 + i*)F/S without exchange risk. If one return exceeds the other, riskless covered arbitrage moves funds until the two are equal.
Economic integration as a prerequisite: arbitrage can equalise returns only if capital moves freely between markets, without capital controls or taxes on flows; the assets are comparable in default and political risk; and transaction costs are low. In segmented markets, such as India before capital account liberalisation, CIP deviations were large.
Among advanced economies CIP held closely before 2008; deviations since then reflect balance-sheet constraints on banks.
Q5(d) · Balance of Payments and Exchange Rates · 10 marks≈ 7 min
Exchange Rate Regimes: Fixed, Floating, Currency Boards and Developing Countries
Under what condition Real Exchange Rate is synonymous to 'terms of trade'? Discuss.
हिंदी में प्रश्न
वास्तविक विनिमय दर किस दशा में 'व्यापार की शर्त' की पर्याय होती है? चर्चा कीजिए।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q5(d)
Approach: Define the real exchange rate (eP*/P) and the terms of trade (Px/Pm), and show that they coincide (inversely) when each country is completely specialised in its export good and P and P* are the prices of exports and imports.
The real exchange rate is R = eP*/P, where e is the nominal exchange rate, P* the foreign price level and P the domestic price level; it measures the price of foreign goods relative to domestic goods. The terms of trade are the price of a country's exports relative to the price of its imports, Px/Pm.
They are synonymous when each country produces and consumes only tradable goods and is completely specialised: the home country produces only its export good, whose price is P (= Px), and the foreign country produces only the good the home country imports, whose price in home currency is eP* (= Pm).
Then R = eP*/P = Pm/Px, the inverse of the terms of trade: a real depreciation (higher R) is exactly a deterioration in the terms of trade.
In reality the condition fails: price indices include non-traded goods, and countries produce many goods, so the real exchange rate measures broad competitiveness while the terms of trade reflect the relative prices of the specific goods traded.
Q5(e) · Economic Development · 10 marks≈ 7 min
Development and Environmental Sustainability
Do you agree whether sustainable use of energy ensures economic sustainability? Explain.
हिंदी में प्रश्न
क्या आप इस से सहमत हैं कि ऊर्जा का धारणीय उपयोग आर्थिक धारणीयता को सुनिश्चित करता है? व्याख्या कीजिए।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q5(e)
Approach: Define sustainable energy use and economic sustainability, show how the first supports the second (natural capital, costs, security, health), then note that it is necessary but not sufficient.
Sustainable energy use means meeting energy needs efficiently from sources that do not deplete finite stocks or overload environmental sinks. Economic sustainability means maintaining income and consumption over time, i.e. keeping the total capital stock (produced, human and natural) from declining.
Sustainable energy supports it: it preserves natural capital and avoids climate damage that would reduce future output; renewables have near-zero marginal cost and protect economies from oil-price shocks and import bills (India imports over 85% of its crude oil); efficiency lowers costs; and cleaner air raises labour productivity.
But it does not by itself ensure economic sustainability, which also needs investment in human and physical capital, sound public finances and institutions; a transition that is too costly or ignores coal-dependent workers and regions can harm growth and equity.
So sustainable energy is a necessary, not a sufficient, condition for economic sustainability, and a just transition is required.

Question 6 (50 marks)

Q6(a) · Economic Development · 15 marks≈ 11 min
Myrdal, Kuznets and Structural Change; Role of Agriculture
Evaluate Kuznets' inverted U shaped curve hypothesis of income distribution. Does it hold good for less developed countries as well?
हिंदी में प्रश्न
कुजनेट्स की आय वितरण उल्टे U आकार वक्र परिकल्पना का मूल्यांकन कीजिए। क्या यह (परिकल्पना) अल्पविकसित देशों के लिये भी सत्य है?
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q6(a)
Approach: Evaluate the hypothesis (statement, mechanism, diagram, supporting and contrary evidence), then judge its validity for less developed countries with examples.
Kuznets's hypothesis (1955) states that inequality rises in the early stages of economic growth, peaks at middle income and falls thereafter. The mechanism is the shift of population from a poor, equal rural sector to a richer, unequal urban sector, together with later forces such as education, urbanisation, demographic change and redistributive politics.
Diagram: Gini coefficient against income per head, an inverted U with the peak at middle income.
Evaluation: Kuznets based it on limited data for the US, UK and Germany and himself called it 'perhaps 5 per cent empirical information and 95 per cent speculation'. Cross-section studies (Ahluwalia, 1976) found an inverted U, but this partly reflected Latin American middle-income countries with high inequality; panel and time-series studies (Deininger and Squire, 1998; Fields) found no systematic pattern. Since 1980 inequality has risen in rich countries, giving a U turn at the top (Piketty).
Less developed countries: the evidence is mixed. Taiwan and South Korea grew rapidly with low and stable inequality because of land reform and mass education, contradicting the rising phase; Brazil reduced inequality in the 2000s through cash transfers; China and India saw inequality rise during fast growth, consistent with the hypothesis. The outcome depends on initial asset distribution, the pattern of growth and policy rather than on income alone.
So the hypothesis is a useful description of one historical path, not a law; for LDCs it implies that inequality can be managed by policy.
Q6(b) · Theories of Growth · 15 marks≈ 11 min
Neo-classical (Solow) and Endogenous Growth: Human Capital and R&D
Does human capital cause economic growth? Explain how human capital formation can be enhanced.
हिंदी में प्रश्न
क्या मानव-पूंजी आर्थिक वृद्धि का कारण है? स्पष्ट कीजिए कि मानव-पूंजी-निर्माण को कैसे बढ़ाया जा सकता है।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q6(b)
Approach: Answer yes with qualifications: theory (Schultz, Lucas, MRW), evidence and the reverse causality problem; then list ways to enhance human capital formation, with Indian examples.
Human capital, the skills, knowledge and health of workers (Schultz, 1961; Becker, 1964), is widely seen as a cause of growth, though causation runs both ways.
Theory: it raises labour productivity; in the Mankiw-Romer-Weil model (1992) it raises the steady-state income level; in Lucas (1988) its accumulation without diminishing returns sustains long-run growth; and educated workers innovate and adopt technology faster (Nelson and Phelps, 1966).
Evidence and caveats: micro studies show high returns to schooling, and East Asia's rapid growth followed big investments in education. But richer countries can afford more education, so growth also causes human capital (Bils and Klenow, 2000), and years of schooling matter less than learning: Hanushek and Woessmann find that cognitive skills, not enrolment, predict growth. So human capital causes growth when its quality is high.
Enhancing human capital formation: (i) universal, quality schooling with a focus on learning outcomes (India's NEP 2020, NIPUN Bharat); (ii) skill development and apprenticeships (Skill India, PM Kaushal Vikas Yojana); (iii) nutrition and health (Poshan Abhiyaan, Ayushman Bharat); (iv) higher education and research quality; (v) women's education, which also lowers fertility; (vi) higher public spending on education, which India's NEP 2020 targets at 6% of GDP.
Thus human capital is a key cause of growth, provided investment yields real skills and is matched by jobs that use them.
Q6(c) · Theories of Growth · 20 marks≈ 14 min
Harrod-Domar Model
Explain how Harrod's warranted rate of growth is similar to Domar's required rate of growth. How has Solow improved upon Harrod-Domar's growth model?
हिंदी में प्रश्न
स्पष्ट कीजिए कि हैरड की वांछित वृद्धि दर एवं डोमर की आवश्यक वृद्धि दर समान हैं। सोलो ने हैरड-डोमर वृद्धि मॉडल को किस प्रकार उन्नत किया है?
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q6(c)
Approach: Derive Gw = s/Cr and Domar's ασ, show they are the same expression under stated equivalences and note differences; then explain Solow's improvements (factor substitution, stable steady state, role of technology) with the diagram.
Similarity: Harrod's warranted rate comes from equating saving sY with accelerator investment Cr·ΔY, giving Gw = s/Cr. Domar's required rate comes from equating the growth of demand (1/α)ΔI with the growth of capacity σI, giving ΔI/I = ασ. Since Domar's α is the saving ratio s and his σ is the output-capital ratio 1/v, ασ = s/v: both are the rate at which income must grow so that saving is absorbed by investment and capacity is fully used. Both assume a fixed saving ratio, a fixed capital-output ratio, no technical change and a closed economy, and both equilibria are unstable.
Difference: Harrod works with income and entrepreneurs' expectations (actual, warranted and natural rates), whereas Domar works with investment and its dual character and does not use the accelerator.
Solow's improvements (1956): (i) a neoclassical production function Y = F(K, L) with constant returns and diminishing returns to each factor allows factor substitution, so the capital-output ratio becomes variable; (ii) the fundamental equation k̇ = sf(k) − (n + δ)k gives a unique, stable steady state where sf(k*) = (n + δ)k*, removing the knife-edge, because Gw adjusts to Gn through changes in k; (iii) long-run growth of per capita income depends on technical progress, not on the saving rate, which only affects the level; (iv) the model predicts conditional convergence and allows growth accounting (the Solow residual).
Diagram: k on the horizontal axis; the curve sf(k) concave and the ray (n + δ)k; they intersect at k*; to the left sf(k) lies above the ray and k rises, to the right it lies below and k falls, so k* is stable.
Solow's own limitation is that technical progress is exogenous, which endogenous growth theory (Romer, Lucas) later addressed.

Question 7 (50 marks)

Q7(a) · Theories of International Trade · 15 marks≈ 11 min
Product Cycle, New Trade Theory and Strategic Trade Policy
Discuss the theory of acquired advantage in international trade using suitable examples.
हिंदी में प्रश्न
उपयुक्त उदाहरणों का उपयोग करते हुए अन्तर्राष्ट्रीय-व्यापार में अर्जित-लाभ के सिद्धान्त की चर्चा कीजिए।
Practise this question Theories of International Trade notes
Model answer
Paper and question: Paper I, Q7(a)
Approach: Contrast natural and acquired (created) advantage, explain how advantage is acquired (learning by doing, scale, R&D, human capital, policy, clusters), with examples (Japan, Korea, India's IT and pharmaceuticals), and note implications.
Classical and H-O theories treat comparative advantage as given by nature: climate, land, minerals and factor endowments. The theory of acquired advantage holds that much of a country's advantage is created over time through investment, learning and policy, so comparative advantage is dynamic.
Sources: (i) learning by doing (Arrow, 1962): costs fall with cumulative output, so early producers gain; (ii) economies of scale and external economies from industrial clusters; (iii) investment in human capital and R&D; (iv) infrastructure and institutions; (v) government policy: infant-industry protection, export promotion, credit and industrial policy; (vi) Michael Porter's 'diamond' (The Competitive Advantage of Nations, 1990): factor conditions, demand conditions, related industries and firm strategy and rivalry.
Illustrations: Japan, a resource-poor country, built advantages in steel, cars and electronics after 1950; South Korea moved from wigs and textiles to ships, semiconductors and phones through targeted policy; Taiwan created a semiconductor industry. India's IT services grew from investment in engineering education and English skills, and its pharmaceutical industry from the process-patent regime of the Patents Act, 1970, which allowed firms to learn reverse engineering.
Implications: advantage can be shaped by policy, but picking winners carries risk of failure and rent-seeking; the acquired-advantage view supports investment in skills and technology rather than permanent protection.
Q7(b) · Balance of Payments and Exchange Rates · 15 marks≈ 11 min
Exchange Rate Regimes: Fixed, Floating, Currency Boards and Developing Countries
Do you think that movement of the nominal exchange rate of Rupee represents a corresponding movement of Indian goods vis-à-vis foreign goods? Explain your position.
हिंदी में प्रश्न
क्या आप के विचार से रुपये के मौद्रिक-विनिमय दर की गतिशीलता, विदेशी वस्तुओं की तुलना में भारतीय वस्तुओं की गतिशीलता को परिलक्षित करती है? अपनी स्थिति को स्पष्ट कीजिए।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q7(b)
Approach: Answer 'not necessarily': distinguish nominal and real exchange rates (and NEER/REER), show that relative price movements depend on inflation differentials, with Indian evidence (rupee depreciation versus stable or appreciating REER), and conclude.
No, not necessarily. The nominal exchange rate (e, rupees per dollar) is the relative price of two currencies; the relative price of Indian and foreign goods is the real exchange rate, R = eP*/P. Only if price levels at home and abroad are unchanged do nominal and real movements coincide.
In percentage terms, %ΔR = %Δe + (foreign inflation − Indian inflation). If India's inflation exceeds that of its partners, the rupee can depreciate in nominal terms while Indian goods become no cheaper, or even dearer, abroad.
Bilateral rates against the dollar also mislead, since India trades with many countries; the relevant measures are the nominal and real effective exchange rates (NEER and REER), trade-weighted indices published by the RBI for a basket of 40 currencies.
Indian evidence: the rupee depreciated from about ₹45 per dollar in 2010 to over ₹80 by 2022, yet the RBI's 40-currency REER remained broadly stable or even appreciated over long periods, because Indian inflation was higher than that of trading partners; so Indian goods did not become correspondingly cheaper. Conversely, in some periods the rupee was stable against the dollar while the REER appreciated, eroding export competitiveness.
Hence nominal movements of the rupee do not by themselves show the movement of Indian goods relative to foreign goods; policy and analysis should focus on the REER, along with productivity and non-price factors.
Q7(c) · Trade Policy, Protection and the WTO · 20 marks≈ 14 min
Trade Blocs, Customs Unions and Monetary Unions
What are the different categories of trade blocks? Are trade blocks beneficial to less developed economies? Justify your answer.
हिंदी में प्रश्न
व्यापार-खण्डों की विभिन्न श्रेणियाँ क्या हैं? क्या व्यापार-खण्ड अल्पविकसित अर्थव्यवस्थाओं के हित में हैं? अपने उत्तर को उचित सिद्ध कीजिए।
Practise this question Trade Policy, Protection and the WTO notes
Model answer
Paper and question: Paper I, Q7(c)
Approach: Classify trade blocs (Balassa's stages: PTA, FTA, customs union, common market, economic union, monetary union) with examples, then weigh benefits and costs for less developed economies (trade creation and diversion, scale, FDI, bargaining power; small markets, similar products, unequal gains, spaghetti bowl), and conclude.
Categories (Bela Balassa, 1961, stages of integration): (i) preferential trade agreement: lower tariffs on some goods; (ii) free trade area: no tariffs among members, each keeps its own external tariff (SAFTA, 2006; ASEAN Free Trade Area; USMCA); (iii) customs union: free trade plus a common external tariff (Southern African Customs Union, Mercosur); (iv) common market: plus free movement of labour and capital; (v) economic union: plus harmonised economic policies (the EU); (vi) monetary union: a common currency and central bank (the euro area).
Benefits for LDCs: (i) trade creation where partners are lower-cost producers; (ii) larger markets that permit economies of scale and industrialisation that small national markets cannot support; (iii) greater competition and efficiency; (iv) attraction of FDI to serve the regional market; (v) collective bargaining power in multilateral negotiations; (vi) regional value chains, as ASEAN countries built in electronics.
Costs and limits: (i) trade diversion towards higher-cost partners; (ii) LDCs often produce similar primary goods and trade little with each other (intra-SAARC trade is about 5% of members' total trade); (iii) gains concentrate in the more industrialised members (Kenya in the old East African Community), causing tensions and break-ups; (iv) loss of tariff revenue; (v) overlapping agreements create a 'spaghetti bowl' of rules of origin (Bhagwati).
Evidence: ASEAN shows successful integration through openness and value chains, while SAFTA and many African blocs achieved little until recent efforts such as the African Continental Free Trade Area (operational from 2021).
Hence trade blocs benefit LDCs when they are open (low external tariffs), include complementary economies and are backed by infrastructure and trade facilitation; inward-looking blocs among similar poor economies bring few gains.

Question 8 (50 marks)

Q8(a) · Public Finance · 15 marks≈ 11 min
Taxation: Sources of Revenue, Forms, Incidence and Effects
If the government raises taxes on labour income and interest income, explain how potential GDP and economic growth are affected.
हिंदी में प्रश्न
यदि सरकार श्रम-आय एवं ब्याज-आय पर कर बढ़ा देती है तो स्पष्ट कीजिए कि सम्भाव्य-सकल-घरेलू-उत्पाद एवं आर्थिक-वृद्धि किस प्रकार प्रभावित होंगे।
Practise this question Public Finance notes
Model answer
Paper and question: Paper I, Q8(a)
Approach: Use the supply-side (tax wedge) framework: a labour income tax affects labour supply and potential GDP; an interest income tax affects saving, investment and capital accumulation, hence growth; state the conditions.
Potential GDP is the output produced when labour is fully employed with the existing capital and technology; economic growth depends on how fast the capital stock, labour and technology expand. Factor-income taxes create a tax wedge between what employers or borrowers pay and what workers or savers receive.
Tax on labour income: labour demand depends on the pre-tax wage and labour supply on the after-tax wage. The tax lowers the after-tax wage; if the substitution effect dominates, workers supply fewer hours, so equilibrium employment falls.
Diagram: labour market with demand LD and supply LS; the tax shifts LS up by the tax to LS + tax; employment falls from L₀ to L₁; through the production function, lower employment gives lower potential GDP.
Tax on interest income: saving depends on the after-tax real interest rate. The tax lowers this return; if the substitution effect dominates, the supply of loanable funds shifts left, the pre-tax real interest rate rises and investment falls. A smaller flow of investment slows capital accumulation, so labour productivity and potential GDP grow more slowly; in Solow's model a lower saving rate lowers the steady-state level of income, and in endogenous growth models it can lower the long-run growth rate itself.
The size of the effect depends on elasticities: if labour supply is backward-bending or saving is income-dominated (target savers), the losses are smaller. The use of the revenue also matters: if it finances infrastructure or education, growth may rise.
Overall, higher taxes on labour and interest income tend to reduce potential GDP and growth, the core of the supply-side case for low marginal rates.
Q8(b) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
IS-LM Model and the Neo-classical Synthesis
Examine the effects of providing public service by a private agency at a lesser price than earlier one on
(i) a closed economy with fixed wages.
(ii) a closed economy with flexible wages.
हिंदी में प्रश्न
एक निजी अभिकरण (एजेन्सी) के द्वारा पूर्व से कमतर कीमत पर सार्वजनिक-सेवा को उपलब्ध कराने के निम्न पर क्या प्रभाव होंगे, व्याख्या कीजिए।
(i) एक बन्द अर्थव्यवस्था स्थिर मजदूरी के साथ
(ii) एक बन्द अर्थव्यवस्था परिवर्तनशील मजदूरी के साथ
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q8(b)
Approach: Interpret the change as a fall in the price (cost) of a service, i.e. a favourable supply shock that lowers the price level, possibly with lower government spending; then analyse it in AD-AS with fixed money wages (upward AS) and with flexible wages (vertical AS).
Interpretation: cheaper private provision of a public service lowers an input cost across the economy, a favourable supply shock that shifts AS right; if government stops spending on it, G falls and AD shifts left.
(i) Fixed money wages: AS slopes upward. The cost reduction shifts it right; the price level falls, real balances M/P rise, the interest rate falls and investment rises, so output and employment increase. The fall in G partly offsets this, but the net effect on output is positive if the supply effect dominates, while the price level falls unambiguously.
(ii) Flexible wages: the labour market clears and the AS curve is vertical at full employment. The cheaper service raises productivity or lowers costs, so full-employment output itself rises (AS shifts right) and the price level falls. Employment stays at full employment; the real wage rises with productivity. A fall in G merely lowers the interest rate and crowds in private investment, changing the composition but not the level of output.
Diagram: two panels in (Y, P) space: (i) upward AS₁ shifting to AS₂ with downward AD, equilibrium moving from E₁ to E₂ at higher Y and lower P (AD₂ to the left if G falls); (ii) vertical AS at Yf shifting to Yf′, with P falling along AD.
Conclusion: the price level falls in both cases; output and employment rise in the short run with fixed wages through demand adjustment, while with flexible wages only potential output changes. This illustrates why efficiency-raising reforms are disinflationary.
Q8(c) · Welfare Economics · 20 marks≈ 14 min
Social Welfare Functions and Arrow's Impossibility Theorem
What is Buchanan's criticism of Arrow's theorem? Show how A. K. Sen proved Arrow's theorem without the overall consistency of social choice to avoid the criticism of Buchanan.
हिंदी में प्रश्न
ऐरो के सिद्धान्त की बुकानन द्वारा की गई आलोचना क्या है? दर्शाइए कि ए. के. सेन ने किस प्रकार बुकानन की आलोचना से बचने के लिये, सामाजिक-चयन की समग्र-स्थिरता की सहायता के बिना ही ऐरो के सिद्धान्त को सिद्ध किया है।
Practise this question Welfare Economics notes
Model answer
Paper and question: Paper I, Q8(c)
Approach: State Buchanan's 1954 objection that 'social rationality' (transitivity) is an illegitimate requirement, then explain Sen's demonstration that Arrow-type impossibility survives without any internal consistency of social choice, because the inter-profile conditions do the work; add the Paretian liberal result.
Arrow's theorem (Social Choice and Individual Values, 1951) shows that no rule aggregating individual orderings into a complete and transitive social ordering can satisfy unrestricted domain, weak Pareto, independence of irrelevant alternatives and non-dictatorship.
Buchanan's criticism ('Social Choice, Democracy, and Free Markets', Journal of Political Economy, 1954): requiring a transitive social ordering attributes individual rationality to 'society', an organic view of the state. Only individuals choose; collective decisions need not be consistent, and the intransitivity of majority voting can even be a virtue, since it prevents a permanent majority.
Sen's response: in 'Internal Consistency of Choice' (Econometrica, 1993) and 'Rationality and Social Choice' (American Economic Review, 1995), Sen reformulated the problem with social choice functions carrying no condition of internal consistency (no transitivity, no consistency across subsets) and still proved an Arrow-type impossibility.
How the proof works: the work is done by conditions linking choices across preference profiles: unrestricted domain, Pareto and independence of irrelevant alternatives. A group decisive over one pair is shown to be decisive over every pair (field expansion), and a decisive group can be shrunk to one person (group contraction), a dictator, without any step needing social transitivity.
Earlier result: Sen's 'Impossibility of a Paretian Liberal' (Journal of Political Economy, 1970) had already shown that even the minimal demand that social choice pick a best element (acyclicity, far weaker than transitivity) conflicts with the Pareto principle and minimal liberty, again sidestepping Buchanan's objection.
Implication: the impossibility arises from the poverty of information used (ordinal, non-comparable rankings), so Sen's constructive route is to admit interpersonal comparisons.

UPSC Mains 2021 Economics Paper II