NSSCO Economics (6145) common mistakes
NSSCO Economics (6145) · Understand the traps and how to avoid them.
When asked to explain the basic economic problem, candidates define it as 'not having enough money' or 'poverty', instead of stating scarcity of resources relative to unlimited wants and the resulting need for choice and opportunity cost.
Everyday use of the word 'scarcity' means shortage or poverty, and candidates carry that meaning into the exam instead of the technical definition involving unlimited wants and limited resources.
What to do instead
Before writing, state the three-part chain explicitly: unlimited wants, limited resources, therefore choice; then name opportunity cost as the cost of the forgone alternative. Practise rewriting the definition in one sentence and applying it to a named example (e.g. a government choosing between a hospital and a road).
On demand and supply questions, candidates shift the curve when the question changes price, or move along the curve when the question changes a non-price factor such as income, tastes or the price of a substitute.
Candidates conflate 'change in demand' with 'change in quantity demanded' because both are described loosely in class as 'demand rising', and they do not systematically classify the cause before drawing.
What to do instead
Adopt a two-step routine: (1) identify the cause named in the question; (2) if it is the good's own price, move along the curve; if it is any other determinant, shift the curve. Label the axis and the shift direction on the diagram and write one sentence stating which determinant changed.
Candidates calculate price elasticity of demand using the wrong formula orientation (price change over quantity change), or omit the minus sign and then mislabel the good as elastic when it is inelastic.
The formula is remembered as a vague 'change over change' fraction, and candidates do not anchor it to the convention that quantity is the numerator because quantity responds to price.
What to do instead
Memorise it as '% change in quantity demanded divided by % change in price' and always write the formula before substituting. Use the midpoint formula when the question gives two price-quantity pairs. Interpret the absolute value: greater than 1 elastic, less than 1 inelastic, equal to 1 unit elastic, and connect elasticity to total revenue direction.
In cost and revenue questions, candidates mix up fixed and variable costs, or confuse total, average and marginal cost, for example treating average cost as the cost of one more unit.
The abbreviations TC, AC and MC look similar and candidates substitute numbers into whichever formula they recall first rather than defining each term before calculating.
What to do instead
Write a one-line definition of each term at the top of your answer space (fixed cost does not vary with output; marginal cost is the change in total cost from one extra unit) and only then calculate. Check the answer against the definition: if output is zero, total cost should equal fixed cost.
Candidates describe profit maximisation as 'producing as much as possible' or 'where revenue is highest', instead of where marginal cost equals marginal revenue (MC = MR).
The intuition that more sales mean more profit is strong, and the MC = MR rule is learned as a formula without the reasoning that profit rises while MR exceeds MC and falls once MC exceeds MR.
What to do instead
Learn the marginal reasoning in words: each extra unit adds MR to revenue and MC to cost; profit rises while MR > MC and stops rising at MR = MC. Practise stating the rule, then explaining why output beyond that point reduces profit, and link it to the profit-maximising diagram for each market structure.
Candidates classify market structures by the number of firms alone, labelling any market with several firms as perfect competition, and ignore the other conditions such as homogeneous products, free entry and perfect information.
Textbook tables list many features, but candidates remember only 'many sellers' because it is the first row, and they do not test each condition against the example given.
What to do instead
Build a checklist of five tests (number of firms, product type, entry barriers, information, price-setting power) and run the example through all five before naming the structure. Practise with awkward cases such as a local taxi rank or a petrol station, where the answer depends on the conditions rather than the count of firms.
On money and banking questions, candidates describe commercial banks and the central bank as doing the same job, for example saying the central bank accepts deposits from the public or that commercial banks issue currency.
Both are called 'banks', and candidates do not separate the functions into a clear two-column comparison, so functions blur under exam pressure.
What to do instead
Memorise two short function lists and keep them distinct: commercial banks take deposits, lend, create credit and provide payment services; the central bank issues currency, acts as banker to government and to commercial banks, holds reserves, and conducts monetary policy. When a question names an institution, tick off which list it belongs to before writing.
Candidates treat GDP and GNP as interchangeable, or count transfer payments and second-hand sales as part of national income when calculating or explaining it.
Both measures are described as 'national income' in everyday discussion, and the exclusion rules (transfers, second-hand goods, intermediate goods) are learned as a list without the reason behind them.
What to do instead
Anchor the distinction: GDP is output produced within the country's borders; GNP is income earned by the country's residents wherever they are. For exclusions, apply the test 'was anything new produced this year?': transfer payments and resales produce nothing new, and intermediate goods are already inside final output, so counting them double-counts.
On inflation and unemployment, candidates describe the wrong policy direction, for example saying the central bank should cut interest rates to reduce inflation, or they confuse demand-pull with cost-push causes.
The transmission mechanism (interest rate to borrowing, spending and prices) is memorised as a phrase rather than a chain, so the direction of the effect is easily reversed under time pressure.
What to do instead
Write the chain in full every time: higher interest rates raise the cost of borrowing, reduce spending and investment, lower aggregate demand and ease demand-pull inflation. Then classify the cause first (demand-pull or cost-push) because cost-push inflation may need supply-side measures rather than demand restraint. Check the direction of every policy statement before moving on.
On balance of payments and exchange rate questions, candidates record a current account deficit as a debit on the balance of payments as a whole, or claim a depreciation always worsens the trade balance.
The double-entry convention (debits and credits, with the accounts summing to zero) is abstract, and candidates apply the everyday meaning of 'deficit is bad' to the mechanics rather than to the accounting rule.
What to do instead
Learn the rule that the balance of payments always balances because a current account deficit is matched by a surplus on the financial/capital account. For depreciation, state the condition: a weaker currency makes exports cheaper and imports dearer, improving the trade balance only if demand is sufficiently price-elastic (the Marshall-Lerner condition) and adjust with a time lag.
On development questions about Namibia, candidates give generic answers such as 'create jobs and grow the economy' without naming a specific characteristic of the Namibian economy or a specific policy instrument.
Development material is often revised as broad themes, and candidates lack a short list of concrete Namibian features and policies to draw on, so they default to generalities that earn little credit.
What to do instead
Prepare a memorised shortlist to deploy by name: small open economy, heavy dependence on mineral exports (diamonds, uranium) and on SACU revenue, exposure to drought and commodity price swings, and policies such as diversification through manufacturing and tourism, SME support and skills development. In each answer, name one feature and link it to one policy and one expected effect.