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What is a Cost-Benefit Analysis and Why is it Useful?

Updated: May 4, 2023


A cost-benefit analysis is a method used to evaluate the potential benefits of a project or decision, compared to its costs and risks, in order to determine if it is economically viable.

A cost-benefit analysis is a method used to evaluate the potential benefits of a project or decision, compared to its costs and risks, in order to determine if it is economically viable.


The goal of this analysis is to determine whether the benefits of a proposed action are worth the costs, and to identify the most cost-effective options. It involves quantifying both the costs and benefits of a decision in monetary terms, and comparing them to determine if the benefits outweigh the costs.


A cost-benefit analysis is different from a feasibility study. While a cost-benefit analysis focuses specifically on the economic viability of a project, a feasibility study considers a wider range of factors, including technical, operational, financial, and economic factors, and provides a comprehensive assessment of the feasibility of a project.



When is a Cost-Benefit Analysis Useful?


A cost-benefit analysis is particularly useful in situations where decisions need to be made about the allocation of resources, where there are trade-offs between benefits and costs, or where multiple options need to be compared to determine the most cost-effective choice. Examples of where a cost-benefit analysis come in useful include:

  1. Project evaluation - A cost-benefit analysis can be used to evaluate the viability of a proposed project, and to determine whether the benefits of the project justify its costs.

  2. Investment decision-making - A cost-benefit analysis can be used to assess the potential benefits and costs of different investment options, and to determine the most cost-effective choice.

  3. Resource allocation - A cost-benefit analysis can be used to determine the most efficient allocation of resources, taking into account the benefits and costs of different options.

  4. Policy analysis - A cost-benefit analysis can be used to evaluate the impact of proposed policy changes, and to determine whether the benefits of a policy change are worth its costs.

  5. Business planning - A cost-benefit analysis can be used in business planning to determine the potential benefits and costs of different strategic options, and to make informed decisions about how to allocate resources.



Key Appraisal Metrics used in a Cost-Benefit Analysis


A cost-benefit analysis typically uses a range of metrics to assess the costs and benefits of a project or decision. The specific metrics used will depend on the nature of the project and the goals of the analysis but some common metrics include:

  • Net Present Value (NPV) - This metric calculates the present value of future benefits and costs, taking into account the time value of money.

  • Internal Rate of Return (IRR) - This metric measures the profitability of an investment, taking into account the costs and benefits over time. It is the discount rate that makes the net present value of all cash flows from an investment equal to zero.

  • Payback Period - This metric measures the amount of time required to recover the costs of an investment.

  • Profitability Index - this index compares the relationship between the costs and benefits of a project by dividing the present value of future cash flows over the initial investment.

  • Benefit-Cost Ratio - This metric compares the total benefits of a project to its total costs, and is often used to determine whether the benefits of a project are worth its costs.

  • Break-even Period - this metric determines the first period when the expected benefits of the project are equal to the costs of that project.



Additional Aspects to Consider in a Cost-Benefit Analysis


Cost-benefit analysis are increasingly considering non-monetary benefits such as environmental impact, social benefits, and community impact. The long-term sustainability of projects, and the potential trade-offs between short-term benefits and long-term costs is another key aspect increasingly being considered.


Cost-benefit analysis are increasing taking into account behavioural insights to better understand how people will respond to new projects and initiatives. They are also increasingly integrated with other methods, such as multicriteria decision analysis and risk analysis, and incorporating the used of 'big data' to provide a more comprehensive evaluation of projects.


These developments reflect the growing importance of a cost-benefit analysis as a tool for decision-making and the increasing sophistication of the method.



Available Resources


Projectify offers user-friendly Excel templates (linked below) to measure the financial feasibility of a proposed project or investment under different scenarios. The templates include the computation of project costs and benefits on a cash flow and profit and loss basis and the calculation of key investment appraisal metrics such as NPV, IRR, payback period, breakeven quarter and profitability index presented both in graphical and table format.


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