Concept Architecture
Concept
Theoretically, Demand Curve is the graphical representation of the relationship between the price of a good or service and the quantity demanded, holding all other determinants constant. It is derived from consumer choice and utility maximisation theory and illustrates the law of demand, whereby quantity demanded generally decreases as price increases. In health economics, the demand curve is used to analyse healthcare utilisation, pharmaceutical consumption, insurance demand, and responses to user charges and reimbursement policies.
Mathematically, the demand curve represents the demand function by plotting price against quantity demanded. The slope of the curve reflects the direction of the relationship, while its curvature determines the responsiveness of demand to price changes. Demand curves provide the basis for elasticity estimation, consumer surplus analysis, and equilibrium modelling.
In practice, demand curves are estimated using observed healthcare utilisation, prescribing, insurance enrolment, or survey data. Econometric techniques are used to estimate demand functions and generate demand curves that support pricing decisions, reimbursement policy evaluation, market forecasting, and analyses of healthcare access and affordability.
Purpose
Used to represent the relationship between price and quantity demanded, supporting analyses of healthcare utilisation, pricing, elasticity, reimbursement policy, and market equilibrium.
Mathematical Formulae
Primary Formula
Linear demand function:
Q? = a ? bP
where:
- Q? = quantity demanded
- P = price
- a = demand intercept
- b = slope coefficient
Supporting Formulae
Inverse demand function:
P = (a ? Q?)?b
Related Mathematical Methods
- Demand function estimation
- Elasticity analysis
- Consumer surplus estimation
- Econometric regression
- Market equilibrium analysis
Example
Demand for an outpatient consultation is represented by:
Q? = 1,000 ? 20P
If the consultation fee is �25:
Q? = 1,000 ? 20(25) = 500
The demand curve predicts that 500 consultations will be demanded at a price of �25.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
=Intercept-(Slope*Price) | =1000-(20*B2) | Estimates quantity demanded at alternative prices. |
| LINEST | =LINEST(C2:C100,B2:B100,TRUE,TRUE) | Estimates the parameters of the demand curve from observed data. |
| FORECAST.LINEAR | =FORECAST.LINEAR(B2,C2:C100,D2:D100) | Forecasts demand at specified prices. |
| SCATTER Chart | Price vs Quantity | Plots the estimated healthcare demand curve. |
VBA (Optional)
Automate estimation of demand curves from utilisation data and generate charts illustrating projected demand under alternative pricing scenarios.
Sources
- Varian HR. Intermediate Microeconomics: A Modern Approach.
- Pindyck RS, Rubinfeld DL. Microeconomics.
- Folland S, Goodman AC, Stano M. The Economics of Health and Health Care.
- Grossman M. On the concept of health capital and the demand for health. Journal of Political Economy. 1972;80(2):223?255.
- Drummond MF, et al. Methods for the Economic Evaluation of Health Care Programmes. Oxford University Press.
Related Concepts (2)
Library
Publications
1
The Economics of Health and Health Care — Folland, Goodman, Stano & Danagoulian, 9th Edition ed., 2024 (Routledge)
The market-leading general health economics textbook, giving comprehensive coverage of health economics through core economic themes and balancing theory, empirical evidence and public policy. The ninth edition adds chapters on health disparities and pandemic economics.
BookView source →
Frequently Asked Questions (6)
What is a demand curve?
A graph showing the relationship between price and quantity demanded, typically sloping downward as consumers buy less when price rises.
Source: Varian 2014
How is a market demand curve built from individual demand?
A market demand curve is formed by adding together the quantities that every individual buyer would purchase at each price, a horizontal summation across consumers. At any given price, the amounts each person demands are summed to give total market demand, and repeating this across prices traces the market curve. Because it aggregates many individual decisions, the market curve is typically smoother and flatter than any single buyer's. Gravelle and Rees (2004) set out this construction from individual demand.
Source: Gravelle & Rees 2004
Why does the demand curve slope downward?
The demand curve slopes downward because, as the price of a good rises, buyers purchase less of it, for two reasons. A higher price makes the good dearer relative to substitutes, so buyers switch toward them, and it reduces buyers' real purchasing power, so they can afford less. Both effects lower the quantity demanded as price rises, producing the downward slope. The curve thus represents the inverse relationship between a good's own price and the quantity buyers will purchase.
Source: Varian 2014
What is the difference between a movement along and a shift of the demand curve?
A movement along the demand curve is a change in quantity demanded caused by a change in the good's own price, tracing from one point on the fixed curve to another. A shift of the curve is a change in demand at every price, caused by a change in another factor, such as income, the prices of related goods, or tastes, moving the whole curve left or right. Distinguishing the two separates the effect of the good's own price from the effect of other influences.
Source: Varian 2014
What causes the demand curve to shift?
The demand curve shifts when a factor other than the good's own price changes: a rise in income, a change in the price of a substitute or complement, a change in tastes, altered expectations, or a change in the number of buyers. Such changes alter the quantity demanded at every price, moving the curve outward if demand increases or inward if it decreases. A change in the good's own price, by contrast, moves along the curve rather than shifting it.
Source: Varian 2014
How is the demand curve used in analysis?
The demand curve is used with the supply curve to determine the market price and quantity, found where the two curves intersect and buyers' and sellers' plans agree. It also shows how quantity demanded responds to price, from which elasticity is read, and how changes in other factors shift demand and alter the equilibrium. In applied work the demand curve helps predict the effects of taxes, subsidies, and price changes, making it a basic instrument for analysing markets.
Source: Varian 2014
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 10 Sep 2025
Content version: 1.0.0
Canonical Identity
- Persistent URI
- https://healtheconomics.wiki/concept/demand-curve
- Term code
- HE-EE-ME-015
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