How do businesses decide whether a long-term investment is worthwhile?
The methods of capital investment appraisal (payback period, accounting rate of return and net present value), how to calculate and interpret each, the time value of money, and the quantitative and qualitative factors in an investment decision.
A focused answer to AQA A-Level Accounting 3.2, covering the methods of capital investment appraisal (payback period, accounting rate of return and net present value), how to calculate and interpret each, the time value of money, and the factors in an investment decision.
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What this dot point is asking
AQA wants you to calculate and interpret the three appraisal methods (payback, accounting rate of return and net present value), explain the time value of money, and weigh the quantitative and qualitative factors in a decision. This is unit 3.2.5, and a full NPV calculation using given discount factors, with an accept or reject decision, is a high-tariff Paper 2 task.
Payback period
Payback is calculated by accumulating the net cash inflows until they equal the initial outlay. With even annual inflows, ; with uneven inflows, accumulate year by year and pro-rate the final part-year. Payback is popular because it is simple and focuses on liquidity and risk, but it is a crude measure of profitability.
Accounting rate of return
Note that ARR uses profit, not cash, so depreciation is deducted, in contrast to the cash-based payback and NPV. Average annual profit is the total profit over the project's life divided by the number of years.
Net present value and the time value of money
The time value of money is the principle that money received later is worth less than money now, because money now could be invested to earn a return (and because of risk and inflation). Net present value (NPV) applies this by discounting each future cash flow to its present value using a discount factor, then subtracting the initial cost. A positive NPV means the project earns more than the discount rate and adds value, so it should be accepted; a negative NPV means it destroys value.
Qualitative factors
A decision also depends on factors beyond the numbers: the risk and reliability of the forecasts (longer projects are more uncertain), the firm's objectives (growth, market share, sustainability), the availability of finance, the effect on staff and reputation, and how the project fits the firm's strategy. The appraisal methods inform the decision; they do not make it.
Try this
Q1. A project costs and returns a year. Calculate the payback period. [2 marks] years.
Q2. Explain why NPV is often preferred to ARR. [3 marks] NPV accounts for the time value of money and uses all the cash flows, whereas ARR ignores timing and uses accounting profit.
Exam-style practice questions
Practice questions written in the style of AQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AQA 20198 marksA project costs 30,000 a year for five years. Using a discount rate of 10% (discount factors: year 1 0.909, year 2 0.826, year 3 0.751, year 4 0.683, year 5 0.621), calculate the payback period and the net present value, and state whether the project should be accepted.Show worked answer →
A full worked NPV; the discounting is the main marking point.
Payback: 90,000 after three years; the remaining 10,000 / $30,000 = one-third of year four, so payback is about 3.3 years (2 marks).
Present values: year 1 30,000 times 0.909 = 24,780; year 3 times 0.751 = 20,490; year 5 times 0.621 = 113,700 (4 marks).
NPV: 100,000 cost = +$13,700 (1 mark). Accept the project, because a positive NPV means it earns more than the 10% required return and adds value (1 mark). Markers reward each discounted inflow, the sum, subtracting the cost, and the accept decision.
AQA 20215 marksEvaluate the use of net present value compared with the payback period for appraising a long-term investment.Show worked answer →
A 5-mark "Evaluate" answer compares strengths and weaknesses and concludes.
NPV strengths: it accounts for the time value of money, uses all the cash flows over the project's life, and gives an absolute money measure of value added (2 marks). Weaknesses: it needs an accurate discount rate and reliable long-term forecasts, and it is harder to calculate and explain.
Payback strengths: simple, focuses on liquidity and risk by favouring quick recovery (1 mark). Weaknesses: ignores cash flows after payback and the time value of money.
Judgement: NPV is theoretically superior for a value-maximising decision, but payback is a useful supplementary measure where cash flow or risk is a concern; many firms use both (2 marks). Markers reward a balanced comparison ending in a supported conclusion.
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Sources & how we know this
- AQA A-level Accounting (7127) specification — AQA (2017)