5 Economic Changes and Project Value

Assessing project value

Economic changes can affect project costs, revenues, financing, and risk. Analysts forecast cash flows under plausible economic conditions and compare their present value with the resources required.

Net present value (NPV) is a common measure of project value:

Here, $B_t$ and $C_t$ are benefits and costs in period $t$, and $r$ is the discount rate. A positive NPV indicates that discounted benefits exceed discounted costs under the assumptions used. Economic forecasts and discounting assumptions should be consistent.

Inflation and relative prices

Inflation is a general rise in prices. It changes the money amount of future costs and revenues, but general inflation alone does not necessarily change a project’s value in real terms. Analysts can use either of two consistent approaches:

• Nominal analysis: Forecast cash flows including expected inflation, then discount them using a nominal rate.

• Real analysis: Remove general inflation from cash flows, then discount them using a real rate.

Do not combine nominal cash flows with a real discount rate, or real cash flows with a nominal discount rate. Adjusting for inflation and discounting are separate steps.

Inflation can affect project value when prices relevant to the project change differently from the general price level. Forecast relative price changes for important inputs and outputs instead of assuming that every price follows the same inflation rate. For example, if construction wages rise faster than general inflation, real construction costs increase.

Interest rates and exchange rates

Interest rates affect the cost of borrowing and the present value assigned to future cash flows through the chosen discount rate. A higher discount rate generally reduces the present value of benefits and costs occurring later, so projects with long payback periods are often especially sensitive to the rate used. Higher borrowing costs can also raise financing expenses, make funding harder to obtain, or change whether an investment is affordable.

Keep financing analysis separate from economic appraisal. Financing rates describe the cost and terms of raising money; an economic discount rate is selected for the appraisal’s purpose and perspective and should not automatically be replaced by a loan rate. Follow the applicable appraisal guidance and keep the cash-flow basis consistent with the discount-rate basis.

Exchange rates matter when a project buys, sells, borrows, or earns revenue in more than one currency. If the domestic currency weakens, imported equipment and foreign-currency debt service may become more expensive in domestic-currency terms, while export revenues may be worth more in domestic-currency terms. A stronger currency can have the opposite effects.

Forecast the currency of each major cost, revenue, and debt obligation, and convert amounts using consistent exchange-rate assumptions. Consider whether exchange-rate changes also affect local prices, demand, or competitors’ costs. In a society-wide economic appraisal, market exchange rates may not always reflect the economic opportunity cost of foreign currency; where relevant, use the prescribed shadow-exchange-rate method.

Input prices and wider conditions

Changes in the prices of fuel, materials, labor, land, or other key inputs can alter operating costs and sometimes capital costs. The effect depends on how much of an input the project uses, when it is needed, and whether substitutes are available. Exposure may be especially high when a scarce or imported input accounts for a large share of total costs.

Distinguish a general price rise from a real increase in an input’s relative price. For example, fuel costs rising faster than general inflation increase real operating costs. Use relevant sector evidence and forecasts, identify major price assumptions, and consider whether contracts, alternative suppliers, or design changes could reduce exposure.

Broader economic conditions can influence both project benefits and costs. A slowdown may reduce customer demand, sales, or usage, while a stronger economy may increase them. Labor-market changes can affect wage costs and the availability of skilled workers. Credit conditions, supply disruptions, commodity-price shocks, and changes in government revenue or policy can also affect implementation, operations, and funding.

Assess these conditions according to the project’s exposure. A toll-road project may depend heavily on traffic and income growth, while a power project may be more exposed to fuel prices, exchange rates, and interest rates. Rather than treating a broad economic forecast as a single adjustment to NPV, identify the specific channels through which it changes cash flows or risks.

Testing uncertainty and responses

Forecasts are uncertain, so test whether the investment decision changes when important assumptions change:

1. Identify the economic variables most likely to affect costs, benefits, or timing.

2. Calculate NPV under plausible low, central, and high assumptions, or under coherent economic scenarios.

3. Use sensitivity analysis to vary one assumption at a time and show its effect on NPV.

4. Find switching values: the value of an assumption at which NPV falls to $0$, or the decision otherwise changes.

5. Consider practical responses such as phased investment, flexible design, contingency allowances, or suitable contracts.

Sensitivity and switching-value analysis help identify which assumptions matter most and where further evidence or risk-management measures may be worthwhile. In applying these tests, maintain consistent cash-flow and discount-rate assumptions, forecast material relative price changes, and account for how the project is exposed to demand, supply, financing, and delivery conditions.