Download clean, printable lists of the most common mistakes students make — so you can fix them before they cost marks.
Each sheet is aligned to its exam board and built from recurring student errors highlighted in examiner reports and mark schemes.
What you get
A topic-by-topic mistakes list with a “do this instead” fix and a quick self-check.
How to use it
Review before past papers, then use the quick checks to catch errors under timed conditions.
Why it works
Many marks are lost on predictable slips: rounding, sign errors, units, and misreading commands.
Coverage by topic
Preview (up to 5 per topic)
16 total rows in download
| Topic | Common mistake / misconception | Do this instead | Quick check |
|---|---|---|---|
| Microeconomics | Drawing diagrams without labelling axes correctly. | Price on y-axis, Quantity on x-axis. Label curves (D, S, D₁, S₁), equilibrium point, and any consumer/producer surplus areas. | Before moving on: axes labelled? Curves labelled? Equilibrium marked? |
| Microeconomics | Saying supply increases when price rises (confusing movement with shift). | Price rise → movement along supply curve (Qs increases). Supply CURVE shifts only when non-price factors change (costs, technology, taxes, subsidies). | Price changes → Qs movement. Non-price factor → S curve shift. |
| Microeconomics | Stating elasticity without explaining the reason. | Always explain WHY: elastic demand because many substitutes / low proportion of income / not a necessity. Examiner expects the reasoning, not just the label. | After stating elastic/inelastic: give at least ONE reason why. |
| Microeconomics | Confusing consumer surplus triangle position. | Consumer surplus = area ABOVE price line and BELOW demand curve. Producer surplus = area BELOW price line and ABOVE supply curve. | CS: triangle above price, below D. PS: triangle below price, above S. |
| Market Failure | Saying externalities only involve pollution. | Externalities can be negative (pollution, congestion) or positive (education benefits, vaccination herd immunity). Many types exist. | Externality = cost or benefit to a third party not in the transaction. Can be positive or negative. |
| Market Failure | Confusing deadweight loss with consumer or producer surplus. | Deadweight loss = welfare lost due to market distortion (tax, subsidy, monopoly). It is the triangle BETWEEN old and new equilibrium quantities. | DWL = welfare that was previously gained but no longer exists due to the distortion. |
| Market Failure | Recommending a tax without assessing the practical difficulties. | A corrective tax must equal the external cost — this is difficult to measure accurately. Also, price elasticity affects whether output actually falls sufficiently. | Evaluate: is the tax set correctly? What if demand is inelastic? Distributional effects? |
| Macroeconomics | Confusing the multiplier effect with the accelerator. | Multiplier: an injection → larger increase in national income. Accelerator: income growth → amplified increase in INVESTMENT (capital spending). | Multiplier: injection → income. Accelerator: income growth → investment. |
| Macroeconomics | Saying expansionary fiscal policy always causes inflation. | Only if the economy is near full employment (inflationary gap). In a recession (deflationary gap), fiscal expansion primarily increases output, not prices. | Check the output gap first. At full employment → inflationary. Below full employment → mainly output effect. |
| Macroeconomics | Confusing monetary policy and fiscal policy. | Monetary policy = central bank changes interest rates/money supply. Fiscal policy = government changes taxation and spending. Different institutions. | Fiscal: government (budget). Monetary: central bank (interest rates, money supply). |
| Macroeconomics | Drawing AD/AS with AD on the vertical axis. | AD/AS model: Price Level on y-axis, Real National Output (GDP) on x-axis. AD slopes downward; SRAS slopes upward; LRAS is vertical. | Y-axis: Price Level. X-axis: Real Output/GDP. LRAS vertical at potential output. |
| Macroeconomics | Saying lower interest rates always reduce inflation. | Lower interest rates stimulate borrowing and spending → increase AD → can cause demand-pull inflation. Higher rates reduce inflation. | Lower rates → more spending → higher AD → potentially more inflation. Higher rates → opposite. |
| International Economics | Confusing absolute and comparative advantage. | Absolute: produces more output with same input. Comparative: lower OPPORTUNITY COST. Trade should be based on COMPARATIVE advantage, even if one country has absolute advantage in all. | Calculate opp. costs for each good. Comparative advantage → lower opp. cost. |
| International Economics | Saying a current account deficit is always a problem. | A CAD can be sustainable if financed by capital inflows, if imports are productive investment goods, or if it reflects high domestic demand. Context matters. | Evaluate: what is causing it? Can it be financed? Is the economy growing? |
| Development | Using GDP per capita as the only development indicator. | GDP per capita misses inequality, distribution, non-monetary welfare. Use HDI (income + education + health), Gini coefficient, infant mortality, etc. | GDP limitations: doesn't measure inequality, sustainability, or non-marketed activity. Use HDI as well. |
| Evaluation | Ending essays with 'it depends' without explaining what it depends on. | 'It depends' is a valid starting point for evaluation but MUST be followed by the specific conditions under which each outcome occurs. | 'It depends on... [specific conditions, e.g. PED, time period, government capacity]' |