GTLE Economics common mistakes
GTLE Economics · Understand the traps and how to avoid them.
When a question gives a demand or supply schedule and asks for the new equilibrium after a shift, the candidate changes only one side of the table and then reads off the old equilibrium price, instead of finding the price where the new quantity demanded equals the new quantity supplied.
Under time pressure the candidate pattern-matches on the familiar word 'equilibrium' and recalls the memorised starting answer, treating the shift as a cosmetic edit rather than recomputing the intersection. Many candidates also never learned to solve the table as a system of simultaneous conditions, so they don't have a procedure to fall back on.
What to do instead
Adopt a fixed three-step routine: write the original demand and supply equations (or columns), apply the shift to exactly the curve named, then solve Qd = Qs for price and substitute back for quantity. Practise ten schedule-to-equation conversions until the routine is automatic, and always sanity-check that the new price moved in the direction the shift predicts.
The candidate labels a good's demand as elastic or inelastic by intuition ('luxuries are elastic, necessities are inelastic') without computing the coefficient, and then answers a revenue question using the wrong elasticity regime.
Textbook examples get memorised as labels attached to product categories, and the candidate never internalises that elasticity is a computed ratio specific to a price range and market. The intuition shortcut usually works on practice items drawn from the same examples, so the weakness stays hidden until an unfamiliar good appears.
What to do instead
For every elasticity item, compute (% change in quantity) / (% change in price) using the midpoint formula, state the coefficient, classify it, and only then reason about total revenue. Drill items with unusual goods and with price ranges where elasticity differs along the same curve.
Asked to distinguish a movement along the production possibilities frontier from a shift of the frontier, the candidate attributes a change in technology or resource endowment to a movement along the curve, or treats unemployment of resources as a shift inward.
The two ideas share the same diagram, and candidates who study by looking at graphs rather than by reasoning about what causes each change conflate 'point moves' with 'curve moves'. The vocabulary of 'shift' and 'movement' is also used loosely in everyday speech.
What to do instead
Build a two-column cause list: changes in the quantities of resources or in technology shift the curve; reallocation of existing fully employed resources, or idling of resources, moves the economy to a different point. Before answering, name the cause in the stem and match it to the correct column.
In a question on comparative advantage, the candidate compares absolute outputs (who produces more with the same inputs) and concludes that the more productive party should specialise in everything, rather than comparing opportunity costs.
Absolute advantage is the more intuitive concept and is the first one taught, so under exam pressure the candidate reaches for the familiar comparison. Opportunity cost requires a per-unit division that candidates often skip when numbers are awkward.
What to do instead
Always compute opportunity cost as 'what is given up divided by what is gained' for each good and each producer, write both fractions, and identify the lower one. If the stem supplies input requirements rather than outputs, invert them first; practise both framings until the inversion is automatic.
On a question about the money multiplier or the effect of an open-market operation, the candidate answers with the direction of the change but not the mechanism, or applies the simple multiplier to a banking system with excess reserves and cash drain.
Candidates memorise the formula 1/reserve ratio and the phrase 'buying bonds increases reserves' without understanding the balance-sheet sequence, so they cannot adjust when the stem adds a complication such as banks holding excess reserves or the public holding currency.
What to do instead
Rehearse the balance-sheet chain explicitly: central bank purchase, bank reserves up, excess reserves created, lending expands, deposits expand, money supply up. Then note the conditions under which the simple multiplier overstates the result, and practise items that add excess reserves or a currency-drain assumption.
The candidate writes lesson objectives such as 'students will understand supply and demand' or 'students will appreciate the role of incentives', then cannot say what evidence would show the objective was met.
Everyday teaching language uses 'understand' and 'know' as objectives, and candidates reproduce the phrasing of their own schooling. Writing observable outcomes requires deliberate practice with a taxonomy, which many candidates have read about but never applied to economics content.
What to do instead
Rewrite each objective with an observable verb and a content-specific condition: 'students will calculate the new equilibrium price and quantity after a demand shift, given a schedule, with at least four of five correct'. Check every objective against the question 'what would I collect as evidence?', and build a bank of economics-specific verbs (calculate, graph, distinguish, evaluate, predict).
When designing an assessment, the candidate writes items that test recall of definitions ('define opportunity cost') while claiming the assessment measures analysis and evaluation, producing a mismatch between stated objectives and the instrument.
Writing higher-order items is harder and slower than writing recall items, and candidates often construct the test first and the table of specifications afterwards, if at all. The mismatch is invisible unless the candidate deliberately maps items to objectives.
What to do instead
Build a specification grid before writing items: list each objective, its cognitive demand, and the number of items and marks allocated. Then write items to fill the cells, and audit the finished paper by labelling each item's demand and confirming the totals match the grid. Include at least one stimulus-based item requiring application to an unfamiliar scenario.
The candidate plans a lesson that uses a real-world example (a local price change, a news headline) purely as an engaging hook, then delivers the economics as definition-and-diagram exposition, so the example is decorative rather than the vehicle for the concept.
Engagement is emphasised in general pedagogy training, so candidates bolt a hook onto a transmission-style lesson and believe they have contextualised the content. Connecting the example back to the model requires subject-specific pedagogical knowledge that is rarely rehearsed.
What to do instead
Design the lesson so the example is the problem students must explain: present the price change, ask students to predict and justify, then introduce the model as the tool that resolves the puzzle, and return to the example at the end for explanation. Write the sequence of teacher questions in the plan so the link is explicit, not incidental.
Faced with a scenario in which a student or colleague discloses something in confidence, or a parent demands a student's marks, the candidate answers from personal instinct about loyalty or helpfulness rather than identifying the applicable duty and the permitted disclosure route.
Candidates prepare for ethics questions by memorising slogans ('act with integrity', 'put students first') and never practise applying a decision procedure to a concrete dilemma with competing duties. Conflicting loyalties feel like matters of character rather than procedure.
What to do instead
Use a fixed analysis for every scenario: identify the parties and their interests, name the specific duty or rule engaged (confidentiality, data protection, safeguarding, assessment integrity), identify who has a legitimate need to know, and state the correct channel and record-keeping. Practise with short scenarios and write the reasoning out in full rather than selecting a slogan.
The candidate treats the professional code of conduct and the legal framework as separate topics, so when a scenario involves both a safeguarding concern and a data-protection question, they address only one and miss the interaction, such as sharing information with the designated officer while not disclosing it more widely.
Revision is organised by syllabus heading, and each heading is revised in isolation, so candidates never practise integrated scenarios. Exam items that combine domains therefore feel unfamiliar even when each component is known.
What to do instead
Revise with integrated case studies: take one scenario and answer it three times, once from the code of conduct, once from the legal or regulatory position, and once from the professional-practice angle, then reconcile the three answers. Keep a one-page map linking each duty in the code to the corresponding legal obligation and the practical procedure.