Deadweight loss, also known as excess burden, is a measure of lost economic efficiency when the socially optimal quantity of a good or a service is not produced. Non-optimal production can be caused by highly concentrated wealth and income (economic inequality), monopoly pricing in the case of artificial scarcity, a positive or negative externality, a tax or subsidy, or a binding price ceiling or price floor such as a minimum wage.
Assume a market for nails where the cost of each nail is $0.10. Demand decreases linearly; there is a high demand for free nails and zero demand for nails at a price per nail of $1.10 or higher. The price of $0.10 per nail represents the point of economic equilibrium in a competitive market.
If market conditions are perfect competition, producers would charge a price of $0.10, and every customer whose marginal benefit exceeds $0.10 would buy a nail. A monopoly producer of this product would typically charge whatever price will yield the greatest profit for themselves, regardless of lost efficiency for the economy as a whole. In this example, the monopoly producer charges $0.60 per nail, thus excluding every customer from the market with a marginal benefit less than $0.60. The deadweight loss due to monopoly pricing would then be the economic benefit foregone by customers with a marginal benefit of between $0.10 and $0.60 per nail. The monopolist has "priced them out of the market", even though their benefit exceeds the true cost per nail.
Conversely, deadweight loss can also arise from consumers buying more of a product than they otherwise would based on their marginal benefit and the cost of production. For example, if in the same nail market the government provided a $0.03 subsidy for every nail produced, the subsidy would reduce the market price of each nail to $0.07, even though production actually still costs $0.10 per nail. Consumers with a marginal benefit of between $0.07 and $0.10 per nail would then buy nails, even though their benefit is less than the real production cost of $0.10. The difference between the cost of production and the purchase price then creates the "deadweight loss" to society.
A tax has the opposite effect of a subsidy. Whereas a subsidy entices consumers to buy a product that would otherwise be too expensive for them in light of their marginal benefit (price is lowered to artificially increase demand), a tax dissuades consumers from a purchase (price is increased to artificially lower demand). This excess burden of taxation represents the lost utility for the consumer. A common example of this is the so-called sin tax, a tax levied against goods deemed harmful to society and individuals. For example, "sin taxes" levied against alcohol and tobacco are intended to artificially lower demand for these goods; some would-be users are priced out of the market, i.e. total smoking and drinking are reduced. Products such as alcohol and tobacco have historically been highly taxed and incur excise duties which are one of the categories of indirect tax. Indirect tax (VAT), weighs on the consumer, is not a cause of loss of surplus for the producer, but affects consumer utility and leads to deadweight loss for consumers. Indirect taxes are usually paid by large entities such as corporations or manufacturers but are partially shifted towards the consumer. Furthermore, indirect taxes can be charged based on the unit price of a said commodity or can be calculated based on a percentage of the final retail price. Additionally, indirect taxes can either be collected at one stage of the production and retail process or alternatively can be charged and collected at multiple stages of the overall production process of a commodity.
Harberger's triangle, generally attributed to Arnold Harberger, shows the deadweight loss (as measured on a supply and demand graph) associated with government intervention in a perfect market. Mechanisms for this intervention include price floors, caps, taxes, tariffs, or quotas. It also refers to the deadweight loss created by a government's failure to intervene in a market with externalities.
In the case of a government tax, the amount of the tax drives a wedge between what consumers pay and what producers receive, and the area of this wedge shape is equivalent to the deadweight loss caused by the tax.
The area represented by the triangle results from the fact that the intersection of the supply and the demand curves are cut short. The consumer surplus and the producer surplus are also cut short. The loss of such surplus is never recouped and represents the deadweight loss.
Some economists like Martin Feldstein maintain that these triangles can seriously affect long-term economic trends by pivoting the trend downwards and causing a magnification of losses in the long run but others like James Tobin have argued that they do not have a huge impact on the economy.
It is important to make a distinction between the Hicksian (per John Hicks) and the Marshallian (per Alfred Marshall) demand function as it relates to deadweight loss. After the consumer surplus is considered, it can be shown that the Marshallian deadweight loss is zero if demand is perfectly elastic or supply is perfectly inelastic. However, Hicks analyzed the situation through indifference curves and noted that when the Marshallian demand curve is perfectly inelastic, the policy or economic situation that caused a distortion in relative prices has a substitution effect, i.e. is a deadweight loss.
In modern economic literature, the most common measure of a taxpayer's loss from a distortionary tax, such as a tax on bicycles, is the equivalent variation, the maximum amount that a taxpayer would be willing to forgo in a lump sum to avoid the distortionary tax. The deadweight loss can then be interpreted as the difference between the equivalent variation and the revenue raised by the tax. The difference is attributable to the behavioral changes induced by a distortionary tax that are measured by a substitution effect. However, that is not the only interpretation, and Lind and Granqvist (2010) point out that Pigou did not use a lump sum tax as the point of reference to discuss deadweight loss (excess burden).
When a tax is levied on buyers, the demand curve shifts downward in accordance with the size of the tax. Similarly, when tax is levied on sellers, the supply curve shifts upward by the size of tax. When the tax is imposed, the price paid by buyers increases, and the price received by seller decreases. Therefore, buyers and sellers share the burden of the tax, regardless of how it is imposed. Since a tax places a "wedge" between the price buyers pay and the price sellers get, the quantity sold is reduced below the level that it would be without tax. To put it another way, a tax on good causes the size of market for that good to decrease.
For example, suppose that Will is a cleaner who is working in the cleaning service company and Amie hired Will to clean her room every week for $100. The opportunity cost of Will's time is $80, while the value of a clean house to Amie is $120. Hence, each of them get same amount of benefit from their deal. Amie and Will each receive a benefit of $20, making the total surplus from trade $40.
However, if the government were to decide to impose a $50 tax upon the providers of cleaning services, their trade would no longer benefit them. Amie would not be willing to pay any price above $120, and Will would no longer receive a payment that exceeds his opportunity cost. As a result, not only do Amie and Will both give up the deal, but Amie has to live in a dirtier house, and Will does not receive his desired income. They have thus lost amount of the surplus that they would have received from their deal, and at the same time, this made each of them worse off to the tune of $40 in value.
Government revenue is also affected by this tax: since Amie and Will have abandoned the deal, the government also loses any tax revenue that would have resulted from wages. This $40 is referred to as the deadweight loss. It causes losses for both buyers and sellers in a market, as well as decreasing government revenues. Taxes cause deadweight losses because they prevent buyers and sellers from realizing some of the gains from trade.
In the graph, the deadweight loss can be seen as the shaded area between the supply and demand curves. While the demand curve shows the value of goods to the consumers, the supply curve reflects the cost for producers. As the example above explains, when the government imposes a tax upon taxpayers, the tax increases the price paid by buyers to Pc and decreases price received by sellers to Pp. Buyers and sellers (Amie and Will) give up the deal between them and exit the market. Thus, the quantity sold reduces from Qe to Qt. The deadweight loss occurs because the tax deters these kinds of beneficial trades in the market.
Price elasticities of supply and demand determine whether the deadweight loss from a tax is large or small. This measures to what extent quantity supplied and quantity demanded respond to changes in price. For instance, when the supply curve is relatively inelastic, quantity supplied responds only minimally to changes in the price. However, when the supply curve is more elastic, quantity supplied responds significantly to changes in price. In other words, when the supply curve is more elastic, the area between the supply and demand curves is larger. Similarly, when the demand curve is relatively inelastic, deadweight loss from the tax is smaller, comparing to more elastic demand curve.
A tax results in deadweight loss as it causes buyers and sellers to change their behaviour. Buyers tend to consume less when the tax raises the price. When the tax lowers the price received by sellers, they in turn produce less. As a result, the overall size of the market decreases below the optimum equilibrium. The elasticities of supply and demand determine to what extent the tax distorts the market outcome. As the elasticities of supply and demand increase, so does the deadweight loss resulting from a tax.
Taxes may be changed by the government or policymakers at different levels. For instance, when a low tax is levied, the deadweight loss is also small (compared to a medium or high tax). An important consideration is that the deadweight loss resulting from a tax increases more quickly than the tax itself; the area of the triangle representing the deadweight loss is calculated using the area (square) of its dimension. Where a tax increases linearly, the deadweight loss increases as the square of the tax increase. This means that when the size of a tax doubles, the base and height of the triangle double. Thus, doubling the tax increases the deadweight loss by a factor of 4.
The varying deadweight loss from a tax also affects the government's total tax revenue. Tax revenue is represented by the area of the rectangle between the supply and demand curves. When a low tax is levied, tax revenue is relatively small. As the size of the tax increases, tax revenue expands. However, when a much higher tax is levied, tax revenue eventually decreases. The higher tax reduces the total size of the market; Although taxes are taking a larger slice of the "pie," the total size of the pie is reduced. Just as in the nail example above, beyond a certain point, the market for a good will eventually decrease to zero.
A deadweight loss occurs with monopolies in the same way that a tax causes deadweight loss. When a monopoly, as a "tax collector," charges a price in order to consolidate its power above marginal cost, it drives a "wedge" between the costs born by the consumer and supplier. Imposing this effective tax distorts the market outcome, and the wedge causes a decrease in the quantity sold, below the social optimum. It is important to remember the difference between the two cases: whereas the government receives the revenue from a genuine tax, monopoly profits are collected by a private firm.
Microeconomics is a branch of mainstream economics that studies the behavior of individuals and firms in making decisions regarding the allocation of scarce resources and the interactions among these individuals and firms. Microeconomics focuses on the study of individual markets, sectors, or industries as opposed to the national economy as whole, which is studied in macroeconomics.
A monopoly, as described by Irving Fisher, is a market with the "absence of competition", creating a situation where a specific person or enterprise is the only supplier of a particular thing. This contrasts with a monopsony which relates to a single entity's control of a market to purchase a good or service, and with oligopoly and duopoly which consists of a few sellers dominating a market. Monopolies are thus characterized by a lack of economic competition to produce the good or service, a lack of viable substitute goods, and the possibility of a high monopoly price well above the seller's marginal cost that leads to a high monopoly profit. The verb monopolise or monopolize refers to the process by which a company gains the ability to raise prices or exclude competitors. In economics, a monopoly is a single seller. In law, a monopoly is a business entity that has significant market power, that is, the power to charge overly high prices, which is associated with a decrease in social surplus. Although monopolies may be big businesses, size is not a characteristic of a monopoly. A small business may still have the power to raise prices in a small industry.
Monopolistic competition is a type of imperfect competition such that there are many producers competing against each other, but selling products that are differentiated from one another and hence are not perfect substitutes. In monopolistic competition, a firm takes the prices charged by its rivals as given and ignores the impact of its own prices on the prices of other firms. If this happens in the presence of coercive government, monopolistic competition will fall into government-granted monopoly. Unlike perfect competition, the firm maintains spare capacity. Models of monopolistic competition are often used to model industries. Textbook examples of industries with market structures similar to monopolistic competition include restaurants, cereal, clothing, shoes, and service industries in large cities. The "founding father" of the theory of monopolistic competition is Edward Hastings Chamberlin, who wrote a pioneering book on the subject, Theory of Monopolistic Competition (1933). Joan Robinson published a book The Economics of Imperfect Competition with a comparable theme of distinguishing perfect from imperfect competition. Further work on monopolistic competition was undertaken by Dixit and Stiglitz who created the Dixit-Stiglitz model which has proved applicable used in the sub fields of international trade theory, macroeconomics and economic geography.
In economics, specifically general equilibrium theory, a perfect market, also known as an atomistic market, is defined by several idealizing conditions, collectively called perfect competition, or atomistic competition. In theoretical models where conditions of perfect competition hold, it has been demonstrated that a market will reach an equilibrium in which the quantity supplied for every product or service, including labor, equals the quantity demanded at the current price. This equilibrium would be a Pareto optimum.
In microeconomics, supply and demand is an economic model of price determination in a market. It postulates that, holding all else equal, in a competitive market, the unit price for a particular good, or other traded item such as labor or liquid financial assets, will vary until it settles at a point where the quantity demanded will equal the quantity supplied, resulting in an economic equilibrium for price and quantity transacted. It forms the theoretical basis of modern economics.
Taxes and subsidies change the price of goods and, as a result, the quantity consumed. There is a difference between an Ad valorem tax and a specific tax or subsidy in the way it is applied to the price of the good. In the end levying a tax moves the market to a new equilibrium where the price of a good paid by buyers increases and the proportion of the price received by sellers decreases. The incidence of a tax does not depend on whether the buyers or sellers are taxed since taxes levied on sellers are likley to be met by raising the price charged to buyers. Most of the burden of a tax falls on the less elastic side of the market because of a lower ability to respond to the tax by changing the quantity sold or bought. Introduction of a subsidy, on the other hand, may either lowers the price of production which encourages firms to produce more, or lowers the price paid by buyers, encouraging higher sales volume. Such a policy is beneficial both to sellers and buyers.
In mainstream economics, economic surplus, also known as total welfare or total social welfare or Marshallian surplus, refers to two related quantities:
Price discrimination is a microeconomic pricing strategy where identical or largely similar goods or services are sold at different prices by the same provider in different markets. Price discrimination is distinguished from product differentiation by the more substantial difference in production cost for the differently priced products involved in the latter strategy. Price differentiation essentially relies on the variation in the customers' willingness to pay and in the elasticity of their demand. For price discrimination to succeed, a firm must have market power, such as a dominant market share, product uniqueness, sole pricing power, etc. All prices under price discrimination are higher than the equilibrium price in a perfectly-competitive market. However, some prices under price discrimination may be lower than the price charged by a single-price monopolist.
In economics, profit maximization is the short run or long run process by which a firm may determine the price, input and output levels that lead to the highest profit. Neoclassical economics, currently the mainstream approach to microeconomics, usually models the firm as maximizing profit.
In economics, economic equilibrium is a situation in which economic forces such as supply and demand are balanced and in the absence of external influences the values of economic variables will not change. For example, in the standard text perfect competition, equilibrium occurs at the point at which quantity demanded and quantity supplied are equal. Market equilibrium in this case is a condition where a market price is established through competition such that the amount of goods or services sought by buyers is equal to the amount of goods or services produced by sellers. This price is often called the competitive price or market clearing price and will tend not to change unless demand or supply changes, and quantity is called the "competitive quantity" or market clearing quantity. But the concept of equilibrium in economics also applies to imperfectly competitive markets, where it takes the form of a Nash equilibrium.
Social cost in neoclassical economics is the sum of the private costs resulting from a transaction and the costs imposed on the consumers as a consequence of being exposed to the transaction for which they are not compensated or charged. In other words, it is the sum of private and external costs. This might be applied to any number of economic problems: for example, social cost of carbon has been explored to better understand the costs of carbon emissions for proposed economic solutions such as a carbon tax.
Allocative efficiency is a state of the economy in which production is aligned with consumer preferences; in particular, every good or service is produced up to the point where the last unit provides a marginal benefit to consumers equal to the marginal cost of producing.
Marginal revenue is a central concept in microeconomics that describes the additional total revenue generated by increasing product sales by 1 unit. To derive the value of marginal revenue, it is required to examine the difference between the aggregate benefits a firm received from the quantity of a good and service produced last period and the current period with one extra unit increase in the rate of production. Marginal revenue is a fundamental tool for economic decision making within a firm's setting, together with marginal cost to be considered.
The tax wedge is the deviation from the equilibrium price and quantity as a result of the taxation of a good. Because of the tax, consumers pay more for the good than they did before the tax, and suppliers receive less for the good than they did before the tax. Put differently, the tax wedge is the difference between the price consumers pay and the value producers receive from a transaction. The tax effectively drives a "wedge" between the price consumers pay and the price producers receive for a product.
In economics, tax incidence or tax burden is the effect of a particular tax on the distribution of economic welfare. Economists distinguish between the entities who ultimately bear the tax burden and those on whom tax is initially imposed. The tax burden measures the true economic weight of the tax, measured by the difference between real incomes or utilities before and after imposing the tax, taking into account how the tax leads prices to change. If a 10% tax is imposed on sellers of butter, for example, but the market price rises 8% as a result, most of the burden is on buyers, not sellers. The concept of tax incidence was initially brought to economists' attention by the French Physiocrats, in particular François Quesnay, who argued that the incidence of all taxation falls ultimately on landowners and is at the expense of land rent. Tax incidence is said to "fall" upon the group that ultimately bears the burden of, or ultimately suffers a loss from, the tax. The key concept of tax incidence is that the tax incidence or tax burden does not depend on where the revenue is collected, but on the price elasticity of demand and price elasticity of supply. As a general policy matter, the tax incidence should not violate the principles of a desirable tax system, especially fairness and transparency. The concept of tax incidence is used in political science and sociology to analyze the level of resources extracted from each income social stratum in order to describe how the tax burden is distributed among social classes. That allows one to derive some inferences about the progressive nature of the tax system, according to principles of vertical equity.
In economics, demand is the quantity of a good that consumers are willing and able to purchase at various prices during a given period of time. The relationship between price and quantity demand is also called the demand curve. Demand for a specific item is a function of an item's perceived necessity, price, perceived quality, convenience, available alternatives, purchasers' disposable income and tastes, and many other options.
In neoclassical economics, a market distortion is any event in which a market reaches a market clearing price for an item that is substantially different from the price that a market would achieve while operating under conditions of perfect competition and state enforcement of legal contracts and the ownership of private property. A distortion is "any departure from the ideal of perfect competition that therefore interferes with economic agents maximizing social welfare when they maximize their own". A proportional wage-income tax, for instance, is distortionary, whereas a lump-sum tax is not. In a competitive equilibrium, a proportional wage income tax discourages work.
The Pacman conjecture holds that durable-goods monopolists have complete market power and so can exercise perfect price discrimination, thus extracting the total surplus. This is in contrast to the Coase conjecture which holds that a durable goods monopolist has no market power, and so price is equal to the competitive market price.
In economics, a factor market is a market where factors of production are bought and sold. Factor markets allocate factors of production, including land, labour and capital, and distribute income to the owners of productive resources, such as wages, rents, etc.
This glossary of economics is a list of definitions of terms and concepts used in economics, its sub-disciplines, and related fields.