Economics (សេដ្ឋកិច្ចវិទ្យា)
The Economics paper covers microeconomic tools, national accounting and policy, and Cambodian applications. Numerical questions are common, so show the formula and the substitution.
Micro tools
- Scarcity forces choice; the cost of a choice is its opportunity cost.
- A change in price moves you along a demand or supply curve; a change in income, tastes, technology or input costs shifts the curve.
- Price elasticity of demand measures responsiveness; demand is more elastic when substitutes exist, when the good is a luxury, and over longer periods.
National accounts
GDP = C + I + G + (X − M). Real GDP strips out price change; GDP counts output inside the country, GNI counts income of residents. Inflation is measured by the consumer price index.
Policy
Fiscal policy uses taxation and public spending; monetary policy uses interest rates, reserve requirements and open-market operations. Cambodia's heavy use of US dollars limits the National Bank's ability to steer interest rates - a point worth stating explicitly.
Worked example
C = 60, I = 20, G = 15, X = 30, M = 25. GDP = 60 + 20 + 15 + (30 − 25) = 100. Note that if imports were 35, GDP would fall to 90: exports add to domestic output, imports leak abroad. Show the substitution and the interpretation; a bare number earns half marks.
Traps
- Using nominal GDP to compare years.
- Mixing fiscal with monetary instruments.
- Writing 'demand rises' when it was supply that shifted.
- Treating dollarisation as costless: it imports US monetary policy and reduces seigniorage.