Concept Architecture
Concept
Theoretically, Price Elasticity of Demand measures the responsiveness of the quantity demanded of a good or service to a change in its own price, holding all other factors constant. It is a fundamental concept in consumer demand theory, reflecting the sensitivity of consumer purchasing behaviour to price changes. The concept exists to quantify the strength of the relationship between price and demand and to support pricing, welfare and policy analysis.
Mathematically, price elasticity of demand is represented as the ratio of the percentage change in quantity demanded to the percentage change in price. The elasticity coefficient provides a unit-free measure of responsiveness that enables comparisons across different goods, markets and populations. Depending on the estimation method, elasticity may be calculated using point elasticity, arc elasticity or econometric demand models.
In practice, price elasticity of demand is estimated using observed market data, household survey data, administrative datasets or experimental evidence. Health economists estimate demand elasticities for healthcare services, pharmaceuticals, insurance, tobacco, alcohol and preventive interventions using regression models, natural experiments and quasi-experimental methods. Estimated elasticities inform pricing policy, taxation, reimbursement decisions and demand forecasting.
Purpose
Used to quantify consumer responsiveness to price changes, estimate the impact of pricing policies, forecast utilisation, evaluate taxation and subsidy interventions, and inform economic evaluations and health policy decision-making.
Mathematical Formulae
Primary Formula
E_d = %?Q_d / %?P
where:
- E_d = price elasticity of demand
- %?Q_d = percentage change in quantity demanded
- %?P = percentage change in price
Supporting Formulae
Point elasticity:
E_d = (dQ / dP) ? (P / Q)
Arc elasticity:
E_d = [(Q? ? Q?) / ((Q? + Q?) / 2)] � [(P? ? P?) / ((P? + P?) / 2)]
Related Mathematical Methods
- Demand function estimation
- Log-linear regression
- Constant elasticity demand models
- Arc elasticity estimation
- Point elasticity estimation
Example
A preventive health screening programme charges �40 per visit and records 10,000 attendances annually. Following a price increase to �44, attendances fall to 9,500.
Percentage change in quantity demanded:
((9500 ? 10000) / 10000) ? 100 = ?5%
Percentage change in price:
((44 ? 40) / 40) ? 100 = 10%
Price elasticity of demand:
E_d = ?5% / 10% = ?0.5
The absolute elasticity is 0.5, indicating relatively inelastic demand. A 10% increase in price results in a 5% reduction in utilisation.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
| Percentage change | =(B2-A2)/A2 | Calculate percentage change in price or quantity |
| Elasticity | =((D2-C2)/C2)/((B2-A2)/A2) | Estimate price elasticity from observed data |
| ABS | =ABS(E2) | Report elasticity as an absolute value for interpretation |
| LN | =LN(C2/C1)/LN(A2/A1) | Estimate constant elasticity using logarithmic changes |
| LINEST | =LINEST(LN(Q2:Q100),LN(P2:P100),TRUE,TRUE) | Estimate elasticity from log-log demand regression |
VBA (Optional)
Automate estimation of price elasticity across multiple health services or products and generate summary reports for demand forecasting and pricing analysis.
Sources
- Drummond MF, Sculpher MJ, Claxton K, Stoddart GL, Torrance GW. Methods for the Economic Evaluation of Health Care Programmes. Oxford University Press.
- Pindyck RS, Rubinfeld DL. Microeconomics. Pearson.
- Varian HR. Intermediate Microeconomics: A Modern Approach. W.W. Norton.
- Nicholson W, Snyder C. Microeconomic Theory: Basic Principles and Extensions. Cengage.
- NICE. Health Technology Evaluation Manual.
Related Concepts (2)
Library
Publications
1
Uncertainty and the Welfare Economics of Medical Care — Kenneth J. Arrow, Vol. 53, No. 5 ed., 1963 (American Economic Review)
The founding paper of health economics as a discipline, analysing how uncertainty, asymmetric information, trust and the special features of medical markets prevent them from behaving like ordinary competitive markets — the intellectual origin of the entire field.
Journal ArticleView source →
Frequently Asked Questions (6)
What is the price elasticity of demand?
A measure of how responsive quantity demanded is to a price change, calculated as percentage change in quantity over percentage change in price.
Source: Varian 2014
How is price elasticity of demand calculated?
Price elasticity of demand is found by dividing the percentage change in the quantity demanded by the percentage change in price that caused it. Because it uses proportional changes, the result is a pure number independent of the units involved, and it is usually negative because quantity falls as price rises. A value beyond minus one signals elastic demand, where quantity responds more than in proportion, and a value between zero and minus one signals inelastic demand. Varian (2014) sets out this calculation.
Source: Varian 2014
How is price elasticity of demand interpreted?
Price elasticity of demand is usually negative, since quantity falls as price rises, and its size is judged by its absolute value. Demand is elastic when the value exceeds one, meaning quantity responds proportionally more than price; inelastic when below one, meaning quantity responds proportionally less; and unit elastic when equal to one. The larger the absolute value, the more sensitive buyers are to price. This classification guides how a price change will affect quantity and revenue.
Source: Varian 2014
What determines the price elasticity of demand?
The price elasticity of demand depends on the availability of substitutes, the good's share of the budget, whether it is a necessity or a luxury, and the time available to adjust. Goods with close substitutes, large budget shares, and luxury status tend to be elastic, since buyers can readily change quantity, while necessities with few substitutes are inelastic. More time to adjust generally raises elasticity, as buyers find alternatives and change habits in response to a price change.
Source: Varian 2014
How does price elasticity relate to revenue?
Price elasticity determines how total revenue responds to a price change. When demand is elastic, a price rise reduces quantity proportionally more, so revenue falls, and a price cut raises revenue. When demand is inelastic, a price rise raises revenue, since quantity falls proportionally less. At unit elasticity, revenue is unchanged. Sellers therefore use elasticity to judge whether raising or lowering price will increase revenue, and it underlies decisions on pricing and on taxing particular goods.
Source: Varian 2014
Why does price elasticity of demand matter in health care?
Price elasticity of demand matters in health care for predicting how patients respond to prices such as co-payments. Much care is relatively inelastic, especially when illness is serious and substitutes are few, so raising the price reduces use only modestly and may deter needed care. Insurance further weakens the response. Knowing the elasticity of different services helps anticipate the effect of cost-sharing on use and spending, and it informs the design of pricing in health policy.
Source: Varian 2014
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 11 Sep 2025
Content version: 1.0.0
Canonical Identity
- Term code
- HE-EE-ME-053
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