Measurement of National Income – Methods & Numericals

1) Why multiple methods?

In theory, the economy’s output can be measured in three equivalent ways:

1. Value of production (value added)
2. Incomes generated in production
3. Expenditure on final goods

So, we have:

• Product/Value-added method
• Income method
• Expenditure method

When done correctly, they should yield the same GDP (up to statistical discrepancy).

2) Product / Value-Added Method (Output method)

2.1 Core formula

For each producing unit (firm/sector):

Then sum value added across all units:

2.2 Why it avoids double counting

Intermediate goods are excluded by subtracting them. Only the additional value created at each stage is counted.

2.3 Practical steps (exam-friendly)

1. Compute gross output of each sector.
2. Subtract intermediate consumption.
3. Sum value added across sectors.
4. Add net indirect taxes if converting FC to MP (depends on data given).

Common caution: If “value of output” already means final output, don’t subtract intermediate again.

3) Income Method

Measures GDP by summing factor incomes generated in domestic territory.

3.1 Typical components

• Compensation of employees (wages, salaries, allowances)
• Rent
• Interest
• Profits (corporate profits, mixed income)
• Mixed income of self-employed

Plus adjustments (depending on presentation):

• add depreciation to go from net to gross,
• add NIT to go from FC to MP.

3.2 What to exclude

• transfer payments (not from current production),
• capital gains from sale of assets,
• income from illegal activities may be excluded in official data (but conceptually it is production).

4) Expenditure Method

Measures GDP by total spending on final goods and services.