Cost-Benefit Analysis

Cost-benefit analysis (CBA) is a form of economic evaluation in which both the costs and the consequences of an intervention are expressed in monetary units, so that the two can be compared directly. By placing benefit and cost on a common money scale, CBA can in principle judge whether an intervention is worth undertaking at all — not merely whether it is better value than a rival — and can compare programmes whose outcomes are otherwise dissimilar.

Definition

Cost-benefit analysis is an economic evaluation that values both the resource costs and the consequences of an intervention in monetary terms and compares them, typically through net social benefit (benefits minus costs) or a benefit-cost ratio, to judge whether and to what extent the intervention is worthwhile.

Scope

This topic covers the logic of monetising health and other consequences, the principal valuation approaches (notably willingness to pay), the net-benefit and benefit-cost-ratio decision rules, and the chief difficulty of valuing health in money. It is a reference treatment of the method, not advice on any specific programme.

Key concepts

• Monetary valuation of consequences
• Willingness to pay (WTP) and willingness to accept
• Net social benefit
• Benefit-cost ratio
• Contingent valuation
• Human-capital versus revealed-preference valuation
• Allocative efficiency and the potential-Pareto (Kaldor-Hicks) criterion

Mechanisms

In CBA the analyst identifies the resources consumed and the consequences produced by an intervention, values both in money, discounts future flows to present value, and forms a decision rule: an option is judged worthwhile if its monetised benefits exceed its costs (positive net benefit) and is preferred among options by the size of that net benefit. Valuing health consequences is the method's distinctive challenge; willingness-to-pay approaches, including contingent-valuation surveys that ask people what they would pay for a benefit or to avoid a harm, aim to express health gains as money grounded in individual preferences, while older human-capital methods valued health through forgone earnings. Because it monetises all consequences, CBA aligns with the potential-Pareto criterion of welfare economics, under which a change is judged desirable if the gainers could in principle compensate the losers.

Clinical relevance

CBA appears in public-health and policy appraisal — for example in evaluating screening, prevention, or environmental-health programmes whose benefits extend beyond health alone. The topic explains how such monetised value judgements are constructed at the population level; it offers no guidance for the care of an individual patient.

Evidence & guidelines

Reference methodology is set out in general texts such as Mishan and Quah's monograph on cost-benefit analysis and in health-specific treatments within Drummond and colleagues' textbook; in health care, cost-utility and cost-effectiveness analysis are more commonly used than full CBA, partly because of the difficulty and contestedness of monetising health.

History

Cost-benefit analysis originated in public-works and welfare economics well before its application to health, drawing on the compensation principle developed by Kaldor and Hicks in the late 1930s. Its extension to health care raised the enduring problem of valuing life and health in money, which led many health economists toward cost-effectiveness and cost-utility analysis, where outcomes need not be monetised, while CBA retained a role where benefits are inherently broad or multi-sectoral.

Debates

Should health and life be valued in money?

Monetising health consequences makes CBA powerful but contentious; willingness-to-pay valuations may reflect ability to pay and raise equity concerns, which is one reason cost-utility analysis, valuing outcomes in quality-adjusted life-years rather than money, is often preferred in health-care appraisal.

Key figures

• Ezra Mishan
• Euston Quah
• Michael Drummond
• Alan Garber

Seminal works

• mishan-quah-2007
• drummond-2015
• weinstein-stason-1977

Frequently asked questions

How does cost-benefit analysis differ from cost-effectiveness analysis?

Cost-benefit analysis values consequences in money, so it can compare programmes with different kinds of outcomes and judge whether a programme is worthwhile in absolute terms. Cost-effectiveness analysis leaves outcomes in natural or utility units, avoiding the need to put a money value on health.

What is willingness to pay in this context?

Willingness to pay is the maximum amount a person would give up to obtain a benefit or avoid a harm. It is used in CBA to express health and other consequences in monetary terms grounded in individual preferences, often elicited through contingent-valuation surveys.