To understand how the quantitative results produced by investment‑appraisal techniques are used to evaluate projects, to compare alternatives, and to inform final investment decisions in line with Cambridge IGCSE/A‑Level syllabus 9609 (10.3).
Definition: The length of time required for cash inflows to recover the initial investment.
Formula (simple pay‑back):
$$\text{Pay‑back Period} = \frac{\text{Initial Investment}}{\text{Average Annual Cash Inflow}}$$| Year | Cash inflow | Cumulative cash flow |
|---|---|---|
| 0 | ‑ Initial outlay | ‑ Initial outlay |
| 1 | CF₁ | ‑ Initial outlay + CF₁ |
| 2 | CF₂ | ‑ Initial outlay + CF₁ + CF₂ |
| … | … | … |
Interpretation:
Limitation: No discounting; unsuitable for long‑term projects.
Definition: The return generated on accounting profit relative to the amount invested.
Formula:
$$\text{ARR} = \frac{\text{Average Annual Accounting Profit}}{\text{Average Investment}}\times100\%$$Interpretation:
Limitation: Based on accrual accounting figures; ignores cash flows and the time value of money.
Definition: The present value of all future cash inflows minus the initial outlay.
Formula (syllabus symbols):
$$NPV = \sum_{t=0}^{n}\frac{C_{t}}{(1+r)^{t}}$$ where \(C_{t}\) = cash flow in period \(t\), \(r\) = required rate of return (discount rate), \(n\) = project life (years).Interpretation:
Limitation: Requires a reliable discount rate; sensitive to forecast errors.
Definition: The discount rate that makes the NPV of a project equal to zero.
Formula (implicit):
$$0 = \sum_{t=0}^{n}\frac{C_{t}}{(1+IRR)^{t}}$$Interpretation:
Limitation: Usually found by trial‑and‑error or a financial calculator; multiple IRRs can be confusing.
Definition: The ratio of the present value of future cash inflows to the initial investment.
Formula:
$$PI = \frac{\displaystyle\sum_{t=1}^{n}\frac{C_{t}}{(1+r)^{t}}}{\text{Initial Investment}}$$Interpretation:
Limitation: Shares the same data requirements as NPV; does not show the absolute amount of value added.
Quantitative results must be weighed against non‑financial considerations. Use the checklist below in exam answers.
| Technique | Primary focus | Considers TVM? | Decision rule | Key limitation |
|---|---|---|---|---|
| Pay‑back Period | Liquidity & risk | No | Pay‑back < Maximum acceptable period | Ignores cash flows after pay‑back and discounting |
| ARR | Accounting profit | No | ARR > Hurdle rate | Based on accrual figures, not cash |
| NPV | Absolute value creation | Yes | NPV > 0 | Requires a reliable discount rate |
| IRR | Rate of return (relative) | Yes | IRR > Required rate of return | Multiple IRRs possible with unconventional cash flows |
| PI | Relative profitability | Yes | PI > 1 | Same data needs as NPV; no absolute value shown |
Vary key assumptions to test the robustness of NPV, IRR or PI. The table below shows three common variables.
| Scenario | Discount rate \(r\) | Sales volume (units) | Variable cost per unit | NPV ($) | IRR (%) | PI |
|---|---|---|---|---|---|---|
| Base case | 10 % | 5,000 | 30 $ | 23,400 | 13.2 | 1.12 |
| Discount + 1 % | 11 % | 5,000 | 30 $ | 15,800 | 12.0 | 1.08 |
| Sales + 20 % | 10 % | 6,000 | 30 $ | 38,600 | 15.1 | 1.19 |
| Variable cost ‑ 5 $ | 10 % | 5,000 | 25 $ | 31,200 | 14.5 | 1.16 |
Project data
| Technique | Calculation | Result | Decision (against criteria) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Pay‑back Period |
Cumulative cash‑flow table
Interpolating: \(2 + \frac{60,000}{70,000}=2.86\) years. |
2.86 years | Accept ( < 4 years ) | ||||||||
| ARR |
Average Accounting Profit = (Profit + Depreciation) – Depreciation
\(=55,000-40,000 = 15,000\) per year Average Investment = \(\dfrac{200,000+0}{2}=100,000\) \(ARR = \dfrac{15,000}{100,000}\times100\% = 15\%\) |
15 % | Accept ( > 12 % ) | ||||||||
| NPV | \[ \begin{aligned} NPV &= -200,000 + \sum_{t=1}^{5}\frac{70,000}{(1.10)^{t}}\\ &= -200,000 + 63,636 + 57,851 + 52,592 + 47,811 + 43,465\\ &= 23,400 \end{aligned} \] | $23,400 | Accept ( > 0 ) | ||||||||
| IRR |
Find \(r\) such that \(\displaystyle\sum_{t=0}^{5}\frac{C_t}{(1+r)^t}=0\). Using trial‑and‑error (or a financial calculator) gives \(IRR \approx 13.2\%\). |
13.2 % | Accept ( > 10 % required ) | ||||||||
| Profitability Index | \[ PI = \frac{\displaystyle\sum_{t=1}^{5}\frac{70,000}{(1.10)^{t}}}{200,000} =\frac{223,400}{200,000}=1.12 \] | 1.12 | Accept ( > 1 ) |
All quantitative criteria are satisfied. The final recommendation must also weigh the qualitative factors listed in section 3 before seeking board approval.
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