First examined by French engineer and economist Jules Dupuit (1804-1866) and later developed by 20th century economists, cost benefit analysis is the determination of the total value of a proposed investment’s inputs and outputs.
Cost benefit analysis examines opportunity costs, externalities, shadow prices and estimates of future interest rates.
The technique was first used in the assessment of projects under the US Flood Control Act, 1936, and received a firmer theoretical underpinning by English economist John Hicks (1904-1989) in a 1943 paper on consumer surpluses.
Cost–benefit analysis (CBA), sometimes also called benefit–cost analysis or benefit costs analysis, is a systematic approach to estimating the strengths and weaknesses of alternatives used to determine options which provide the best approach to achieving benefits while preserving savings (for example, in transactions, activities, and functional business requirements). A CBA may be used to compare completed or potential courses of actions, or to estimate (or evaluate) the value against the cost of a decision, project, or policy. It is commonly used in commercial transactions, business or policy decisions (particularly public policy), and project investments.
CBA has two main applications:
To determine if an investment (or decision) is sound, ascertaining if – and by how much – its benefits outweigh its costs.
To provide a basis for comparing investments (or decisions), comparing the total expected cost of each option with its total expected benefits.
CBA is related to cost-effectiveness analysis. Benefits and costs in CBA are expressed in monetary terms and are adjusted for the time value of money; all flows of benefits and costs over time are expressed on a common basis in terms of their net present value, regardless of whether they are incurred at different times. Other related techniques include cost–utility analysis, risk–benefit analysis, economic impact analysis, fiscal impact analysis, and social return on investment (SROI) analysis.
Cost–benefit analysis is often used by organizations to appraise the desirability of a given policy. It is an analysis of the expected balance of benefits and costs, including an account of any alternatives and the status quo. CBA helps predict whether the benefits of a policy outweigh its costs (and by how much), relative to other alternatives. This allows the ranking of alternative policies in terms of a cost–benefit ratio. Generally, accurate cost–benefit analysis identifies choices which increase welfare from a utilitarian perspective. Assuming an accurate CBA, changing the status quo by implementing the alternative with the lowest cost–benefit ratio can improve Pareto efficiency. Although CBA can offer an informed estimate of the best alternative, a perfect appraisal of all present and future costs and benefits is difficult; perfection, in economic efficiency and social welfare, is not guaranteed.
The value of a cost–benefit analysis depends on the accuracy of the individual cost and benefit estimates. Comparative studies indicate that such estimates are often flawed, preventing improvements in Pareto and Kaldor–Hicks efficiency. Interest groups may attempt to include (or exclude) significant costs in an analysis to influence its outcome.
Small, blue-tinted picture of Jules Depuit
French engineer and economist Jules Dupuit, credited with the creation of cost–benefit analysis
The concept of CBA dates back to an 1848 article by Jules Dupuit, and was formalized in subsequent works by Alfred Marshall. Jules Dupuit pioneered this approach by first calculating “the social profitability of a project like the construction of a road or bridge” In an attempt to answer this, Dupuit began to look at the utility users would gain from the project. He determined that the best method of measuring utility is by learning one’s willingness to pay for something. By taking the sum of each user’s willingness to pay, Dupuit illustrated that the social benefit of the thing (bridge or road or canal) could be measured. Some users may be willing to pay nearly nothing, others much more, but the sum of these would shed light on the benefit of it. It should be reiterated that Dupuit was not suggesting that the government perfectly price-discriminate and charge each user exactly what they would pay. Rather, their willingness to pay provided a theoretical foundation on the societal worth or benefit of a project. The cost of the project proved much simpler to calculate. Simply taking the sum of the materials and labor, in addition to the maintenance afterward, would give one the cost. Now, the costs and benefits of the project could be accurately analyzed, and an informed decision could be made.
The Corps of Engineers initiated the use of CBA in the US, after the Federal Navigation Act of 1936 mandated cost–benefit analysis for proposed federal-waterway infrastructure. The Flood Control Act of 1939 was instrumental in establishing CBA as federal policy, requiring that “the benefits to whomever they accrue [be] in excess of the estimated costs.”
CBA’s application to broader public policy began with the work of Otto Eckstein, who laid out a welfare economics foundation for CBA and its application to water-resource development in 1958. It was applied in the US to water quality,recreational travel, and land conservation during the 1960s, and the concept of option value was developed to represent the non-tangible value of resources such as national parks.
CBA was expanded to address the intangible and tangible benefits of public policies relating to mental illness, substance abuse, college education, and chemical waste. In the US, the National Environmental Policy Act of 1969 required CBA for regulatory programs; since then, other governments have enacted similar rules. Government guidebooks for the application of CBA to public policies include the Canadian guide for regulatory analysis, the Australian guide for regulation and finance, and the US guides for health-care and emergency-management programs.
CBA for transport investment began in the UK with the M1 motorway project and was later used for many projects, including the London Underground’s Victoria line. The New Approach to Appraisal (NATA) was later introduced by the Department for Transport, Environment and the Regions. This presented balanced cost–benefit results and detailed environmental impact assessments. NATA was first applied to national road schemes in the 1998 Roads Review, and was subsequently rolled out to all transport modes. Maintained and developed by the Department for Transport, it was a cornerstone of UK transport appraisal in 2011.
The European Union’s Developing Harmonised European Approaches for Transport Costing and Project Assessment (HEATCO) project, part of the EU’s Sixth Framework Programme, reviewed transport appraisal guidance of EU member states and found significant national differences. HEATCO aimed to develop guidelines to harmonise transport appraisal practice across the EU.
Transport Canada promoted CBA for major transport investments with the 1994 publication of its guidebook. US federal and state transport departments commonly apply CBA with a variety of software tools, including HERS, BCA.Net, StatBenCost, Cal-BC, and TREDIS. Guides are available from the Federal Highway Administration, Federal Aviation Administration, Minnesota Department of Transportation, California Department of Transportation (Caltrans), and the Transportation Research Board’s Transportation Economics Committee.
In the case of the Ford Pinto (where, because of design flaws, the Pinto was liable to burst into flames in a rear-impact collision), the company decided not to issue a recall. Ford’s cost–benefit analysis had estimated that based on the number of cars in use and the probable accident rate, deaths due to the design flaw would cost it about $49.5 million in wrongful death lawsuits; a recall would cost $137.5 million. The company failed to consider the costs of negative publicity, which forced a recall and reduced Ford sales.
In health economics, CBA may be an inadequate measure because willingness-to-pay methods of determining the value of human life can be influenced by income level. Variants, such as cost–utility analysis, QALY and DALY to analyze the effects of health policies, may be more suitable.
For some environmental effects, cost–benefit analysis can be replaced by cost-effectiveness analysis. This is especially true when one type of physical outcome is sought, such as a reduction in energy use by an increase in energy efficiency. Using cost-effectiveness analysis is less laborious and time-consuming, since it does not involve the monetization of outcomes (which can be difficult in some cases).
It has been argued that if modern cost–benefit analyses had been applied to decisions such as whether to mandate the removal of lead from gasoline, block the construction of two proposed dams just above and below the Grand Canyon on the Colorado River, and regulate workers’ exposure to vinyl chloride, the measures would not have been implemented (although all are considered highly successful) The US Clean Air Act has been cited in retrospective studies as a case in which benefits exceeded costs, but knowledge of the benefits (attributable largely to the benefits of reducing particulate pollution) was not available until many years later.
Also see: consumer surplus, compensation principle, social welfare function