Prices And Welfare

This book provides a general framework for the use of theoretical contributions in empirical works, addressing the question of what is the effect of a price change on household well-being. This simple question is one of the most relevant and controversial questions in microeconomic theory and one of the main sources of errors in empirical economics. In particular, this book aims to 1) Review the essential microeconomics literature since the first seminal papers by Hicks in the 1930s; 2) Organize and simplify this literature in a way that can be easily used by analysts with different backgrounds providing algebraic, geometric and computational illustrations; 3) identify and measure the essential differences across methods and test how these differences affect empirical results; 4) Provide guidelines for the use of alternative approaches under imperfect information on utility, demand systems, elasticities and more generally incomes and quantities; 5) Provide computational codes in Stata for the application of all methods. The focus of the book is on developing economies and the poor, and the assumptions made will relate primarily to these countries and group of people, presumably the main policy focus of international organizations and national governments.

This paper explores the impacts of the Trump administration's trade policy on prices and welfare. Over the course of 2018, the U.S. experienced substantial increases in the prices of intermediates and final goods, dramatic changes to its supply-chain network, reductions in availability of imported varieties, and complete passthrough of the tariffs into domestic prices of imported goods. Overall, using standard economic methods, we find that the full incidence of the tariff falls on domestic consumers, with a reduction in U.S. real income of $1.4 billion per month by the end of 2018. We also see similar patterns for foreign countries who have retaliated against the U.S., which indicates that the trade war also reduced real income for other countries.

The financial crisis in the advanced countries that began in 2007 has led central bankers to adopt unconventional policy measures as policy interest rates neared the zero bound. One suggestion (Blanchard, Dell’Ariccia, and Mauro, 2010) has been to raise inflation targets to provide more room for policy rate easing during crises. This paper addresses a different issue: the relationship between inflation and welfare. The literature is surveyed and a model is developed. A key conclusion is that an increase in inflation targets gives rise to additional welfare costs, even after the extra room to maneuver above the zero lower bound for nominal policy rates is taken into account. Based on parameter values that fit U.S. data, the additional welfare costs of raising inflation targets from 2 to 4 percent are estimated at about 0.3 percent of annual real income. A rise to 10 percent would yield additional welfare costs of about 1 percent of real income. Other parameter values yield welfare costs as high as 7 (respectively 30) percent of real income for raising inflation targets from 2 to 4 (respectively from 2 to 10) percent. The full costs of raising inflation targets are likely to be higher because the model used to generate these estimates does not account for higher inflation-induced volatility.

What is the effect of a new infrastructure on the well-being of a local community? Is a tax reform desirable? Does the privatization of a telecommunication provider increase social welfare? To answer these questions governments and their policy advisors should have in mind an operative definition of social welfare, and cannot rely on simple official statistics, such as GDP. The price we observe are often misleading as welfare signals, and costs and benefits for the society should be based on ‘shadow prices’, revealing the social opportunity costs of goods and of changes of the world. This book explains how to apply these welfare economics ideas to the real world. After a theoretical discussion of the concept of social welfare, a critical analysis of the traditional doctrine of welfare economics embodied in the Two Fundamental Theorems, and a presentation of social cost-benefit analysis, the book introduce the readers to an applied framework. This includes the empirical estimation of shadow prices of goods, of the social cost of labour and capital, the assessment of risk. This book also includes the state of the art of international experience with CBA, including ex-post evaluation of major projects, economic rates of return in different sectors, and a case study on privatisation, is presented. This book offers a unique and original blend of theory, empirics and experience. The theoretical discussion clarifies why shadow prices are not virtual market equilibrium prices, as they arise as the solution of a planning problem, often with governments and economic agents constrained in their information and powers. The empirical chapters show how to compute proxies of the shadow prices in simple ways. The experience chapters draw from first hand research, gained by the Author and his collaborators over many years of advisory work for the European Commission and other international and national institutions.

For over 50 years economists have argued that where private costs or benefits differ from social costs or benefits - in noise, smells, congestion, pollution of the environment - there is a 'clear case' for government intervention to correct the divergence. This argument has been used to justify almost endless intervention. However, the original analysts of social costs/benefits were led into error by failing to test their propositions against the evidence of real life. Painstaking empirical studies clearly demonstrate these errors. A divergence between private and social cost is no decisive justification for government action to correct it. The costs of intervention often outweigh the social benefits. Moreover, the alleged 'externalities' are merely uncontracted effects. Under private property rights, the use of contracts to transact what have been regarded as 'external' effects is far more common than has been commonly recognised.

What is the welfare effect of a price change? This simple question is one of the most relevant and controversial questions in microeconomic theory and its different answers can lead to severe heterogeneity in empirical results. This paper returns to this question with the objective of providing a general framework for the use of theoretical contributions in empirical works, with a particular focus on poor people and poor countries. Welfare measures (such as Equivalent Variation or Consumer's Surplus) and computational methods (such as Taylor's approximations or the Vartia method) are compared to test how these choices result in different welfare measurement under different price shock scenarios. As a rule of thumb and irrespective of parameter choices, welfare measures converge to approximately the same result for price changes below 10 percent. Above this threshold, these measures start to diverge significantly. Budget shares play an important role in explaining such divergence, whereas the choice of demand system has a minor role. Under standard utility assumptions, the Laspeyers and Paasche variations are always the outer bounds of welfare estimates and consumer surplus is always the median estimate. The paper also introduces a new simple welfare approximation, clarifies the relation between Taylor's approximations and the income and substitution effects, and provides an example for treating nonlinear pricing. Stata codes for all computations are provided in annex.