In economics and particularly in consumer choice theory, the substitution effect is one component of the effect of a change in the price of a good upon the amount of that good demanded by a consumer, the other being the income effect.
When a good's price decreases, if hypothetically the same consumption bundle were to be retained, income would be freed up which could be spent on a combination of more of each of the goods. Thus the new total consumption bundle chosen, compared to the old one, reflects both the effect of the changed relative prices of the two goods (one unit of one good can now be traded for a different quantity of the other good than before as the ratio of their prices has changed) and the effect of the freed-up income. The effect of the relative price change is called the substitution effect, while the effect due to income having been freed up is called the income effect .
If income is altered in response to the price change such that a new budget line is drawn passing through the old consumption bundle but with the slope determined by the new prices and the consumer's optimal choice is on this budget line, the resulting change in consumption is called the Slutsky substitution effect. The idea is that the consumer is given enough money to purchase his old bundle at the new prices, and his choice changes are seen.
If instead, a new budget line is found with the slope determined by the new prices but tangent to the indifference curve going through the old bundle, the difference between the new point of tangency and the old bundle is the Hicks substitution effect. The idea now is that the consumer is given just enough income to achieve his old utility at the new prices, and how his choice changes is seen. The Hicks substitution effect is illustrated in the next section.
Some authors refer to one of these two concepts as simply the substitution effect. The popular textbook by Varian [1] describes the Slutsky variant as the primary one, but also gives a good explanation of the distinction.
The same concepts also apply if the price of one good goes up instead of down, with the substitution effect reflecting the change in relative prices and the income effect reflecting the fact the income has been soaked up into additional spending on the retained units of the now-pricier good.
For example, consider coffee and tea. If the price of coffee increased, consumers of hot drinks may decide to start drinking tea instead. This will cause the demand for tea to increase. Likewise, if the price of coffee was to decrease, tea-drinkers may decide to shift their drinking habits and substitute coffee for their daily drinking habits, causing the demand for tea to decrease.
Economists had long understood that changes in price could lead to two main responses by consumers, initial work on this subject had been done by Vilfredo Pareto in the 1890s, but it wasn't until Eugen Slutsky’s 1915 article that rigor was brought to the subject. Because Slutsky’s original paper was published during World War I in Italian, economists in the Anglo-American world did not become aware of Slutsky’s contributions until the 1930s. [2] The English world was fully introduced to Slutsky's ideas in 1934 when "A Reconsideration of the Theory of Value" was published by John Hicks and RGD Allen, this paper built upon work by Pareto and came to conclusions Slutsky had realized two decades prior. [3]
Suppose the initial situation is given by the graph (with good Y plotted horizontally) with the indicated (and never-changing) indifference curves shown and with budget constraint BC1 and with the consumer choosing point A because it puts him on the highest possible indifference curve consistent with BC1. The position and slope of the budget constraint are based on the consumer's income and on the prices of the two goods X and Y. If the price of Y falls, the budget constraint pivots to BC2, with a greater intercept of good Y because if all income were spent on Y more of it could be purchased at the now-lower price. The overall effect of the price change is that the consumer now chooses the consumption bundle at point C.
But the move from A to C can be decomposed into two parts. The substitution effect is the change that would occur if the consumer were required to remain on the original indifference curve; this is the move from A to B. The income effect is the simultaneous move from B to C that occurs because the lower price of one good in fact allows movement to a higher indifference curve. (In this graph Y is an inferior good since C is to the left of B so Y2 < Ys.)
The concept of the elasticity of substitution was developed by two different economists, each with their own focus. One of these economists was John Hicks, who defined elasticity of substitution as the change in percentage in the relative number of factors of production used, given a particular change in percentage in relative prices or marginal products. This definition is also known as the direct elasticity of substitution. The other economist was Joan Robinson, who defined elasticity of substitution as the change in proportion of the ratio of the number of factors used divided by the change in proportion of the ratio of each factor's prices. These two definitions function in the same way when limited to two factors of production. [4]
In economics, utility is a measure of the satisfaction that a certain person has from a certain state of the world. Over time, the term has been used in at least two different meanings.
In economics, an indifference curve connects points on a graph representing different quantities of two goods, points between which a consumer is indifferent. That is, any combinations of two products indicated by the curve will provide the consumer with equal levels of utility, and the consumer has no preference for one combination or bundle of goods over a different combination on the same curve. One can also refer to each point on the indifference curve as rendering the same level of utility (satisfaction) for the consumer. In other words, an indifference curve is the locus of various points showing different combinations of two goods providing equal utility to the consumer. Utility is then a device to represent preferences rather than something from which preferences come. The main use of indifference curves is in the representation of potentially observable demand patterns for individual consumers over commodity bundles.
This aims to be a complete article list of economics topics:
In economics, elasticity measures the responsiveness of one economic variable to a change in another. For example, if the price elasticity of the demand of a good is -2, then a 10% increase in price will cause the quantity demanded to fall by 20%. Elasticity in economics provides an understanding of changes in the behavior of the buyers and sellers with price changes. There are two types of elasticity for demand and supply, one is inelastic demand and supply and the other one is elastic demand and supply.
The theory of consumer choice is the branch of microeconomics that relates preferences to consumption expenditures and to consumer demand curves. It analyzes how consumers maximize the desirability of their consumption, by maximizing utility subject to a consumer budget constraint. Factors influencing consumers' evaluation of the utility of goods include: income level, cultural factors, product information and physio-psychological factors.
In economics, a budget constraint represents all the combinations of goods and services that a consumer may purchase given current prices within their given income. Consumer theory uses the concepts of a budget constraint and a preference map as tools to examine the parameters of consumer choices. Both concepts have a ready graphical representation in the two-good case. The consumer can only purchase as much as their income will allow, hence they are constrained by their budget. The equation of a budget constraint is where is the price of good X, and is the price of good Y, and m is income.
In economics, inferior goods are those goods the demand for which falls with increase in income of the consumer. So, there is an inverse relationship between income of the consumer and the demand for inferior goods. There are many examples of inferior goods, including cheap cars, public transit options, payday lending, and inexpensive food. The shift in consumer demand for an inferior good can be explained by two natural economic phenomena: the substitution effect and the income effect.
In microeconomics, substitute goods are two goods that can be used for the same purpose by consumers. That is, a consumer perceives both goods as similar or comparable, so that having more of one good causes the consumer to desire less of the other good. Contrary to complementary goods and independent goods, substitute goods may replace each other in use due to changing economic conditions. An example of substitute goods is Coca-Cola and Pepsi; the interchangeable aspect of these goods is due to the similarity of the purpose they serve, i.e. fulfilling customers' desire for a soft drink. These types of substitutes can be referred to as close substitutes.
Welfare economics is a field of economics that applies microeconomic techniques to evaluate the overall well-being (welfare) of a society.
In economics and particularly in consumer choice theory, the income-consumption curve is a curve in a graph in which the quantities of two goods are plotted on the two axes; the curve is the locus of points showing the consumption bundles chosen at each of various levels of income.
In microeconomics, the law of demand is a fundamental principle which states that there is an inverse relationship between price and quantity demanded. In other words, "conditional on all else being equal, as the price of a good increases (↑), quantity demanded will decrease (↓); conversely, as the price of a good decreases (↓), quantity demanded will increase (↑)". Alfred Marshall worded this as: "When we say that a person's demand for anything increases, we mean that he will buy more of it than he would before at the same price, and that he will buy as much of it as before at a higher price". The law of demand, however, only makes a qualitative statement in the sense that it describes the direction of change in the amount of quantity demanded but not the magnitude of change.
In economics, a complementary good is a good whose appeal increases with the popularity of its complement. Technically, it displays a negative cross elasticity of demand and that demand for it increases when the price of another good decreases. If is a complement to , an increase in the price of will result in a negative movement along the demand curve of and cause the demand curve for to shift inward; less of each good will be demanded. Conversely, a decrease in the price of will result in a positive movement along the demand curve of and cause the demand curve of to shift outward; more of each good will be demanded. This is in contrast to a substitute good, whose demand decreases when its substitute's price decreases.
Utility maximization was first developed by utilitarian philosophers Jeremy Bentham and John Stuart Mill. In microeconomics, the utility maximization problem is the problem consumers face: "How should I spend my money in order to maximize my utility?" It is a type of optimal decision problem. It consists of choosing how much of each available good or service to consume, taking into account a constraint on total spending (income), the prices of the goods and their preferences.
In microeconomics, the Slutsky equation, named after Eugen Slutsky, relates changes in Marshallian (uncompensated) demand to changes in Hicksian (compensated) demand, which is known as such since it compensates to maintain a fixed level of utility.
In microeconomics, a consumer's Hicksian demand function or compensated demand function for a good is their quantity demanded as part of the solution to minimizing their expenditure on all goods while delivering a fixed level of utility. Essentially, a Hicksian demand function shows how an economic agent would react to the change in the price of a good, if the agent's income was compensated to guarantee the agent the same utility previous to the change in the price of the good—the agent will remain on the same indifference curve before and after the change in the price of the good. The function is named after John Hicks.
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 the tax is initially imposed. The tax burden measures the true economic effect of the tax, measured by the difference between real incomes or utilities before and after imposing the tax, and taking into account how the tax causes prices to change. For example, if a 10% tax is imposed on sellers of butter, but the market price rises 8% as a result, most of the tax 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.
A relative price is the price of a commodity such as a good or service in terms of another; i.e., the ratio of two prices. A relative price may be expressed in terms of a ratio between the prices of any two goods or the ratio between the price of one good and the price of a market basket of goods.
In microeconomics, the property of local nonsatiation (LNS) of consumer preferences states that for any bundle of goods there is always another bundle of goods arbitrarily close that is strictly preferred to it.
In consumer theory, a consumer's preferences are called homothetic if they can be represented by a utility function which is homogeneous of degree 1. For example, in an economy with two goods , homothetic preferences can be represented by a utility function that has the following property: for every :
In economics, and in other social sciences, preference refers to an order by which an agent, while in search of an "optimal choice", ranks alternatives based on their respective utility. Preferences are evaluations that concern matters of value, in relation to practical reasoning. Individual preferences are determined by taste, need, ..., as opposed to price, availability or personal income. Classical economics assumes that people act in their best (rational) interest. In this context, rationality would dictate that, when given a choice, an individual will select an option that maximizes their self-interest. But preferences are not always transitive, both because real humans are far from always being rational and because in some situations preferences can form cycles, in which case there exists no well-defined optimal choice. An example of this is Efron dice.