Ricerche Economiche最新文献

The theoretical conditions under which we can estimate the parameters of micro demand behaviour from aggregate data are now well understood. Using a time series of Canadian micro data we investigate whether these conditions hold. We find that they do not. We conclude that estimates of micro parameters that are derived from aggregate time-series data alone have dubious validity.

This paper investigates aggregate behaviour using multiple indexes, assuming that micro behaviour is consistent with economic theory but unrestricted otherwise. The focus is on meanspread characterizations of the distribution of the relevant characteristics across micro units. Special attention is given to price dispersion. A number of testable hypotheses are derived on the properties of aggregate behaviour without assuming the existence of a representative agent.

The behaviour of agents and the distribution of agents play equivalent and joint roles in determining macroeconomic relationships. A general characterization of the joint restrictions on preferences and distributions of consumers that rationalize a representative consumer is provided. Linear Engel curves and social welfare maximizing income distributions are shown to be polar examples of this general characterization. Joint restrictions that lie between these extremes, employing regularities in both consumers' preferences and the distribution of income, can explain the empirical observation that macroeconomic demands resemble a non-linear representative consumer. Similar joint regularities in behaviour and distributions are likely to account for many observed macroeconomic regularities.

The past literature on aggregation theory is surveyed in terms of three nested formal models. The most general one distinguishes exogenous and endogenous variables, both for a micro- and a corresponding macro-model; it shows why the main problem lies in aggregation of exogenous variables; it suffices in particular for Leontief's results on commodity aggregates. The aggregation of economic relations further assumes that the micro-model is individualized; the case of aggregate production functions shows how varied are the micro-models that may be selected for the discussion. The statistical approach, moreover, introduces the distribution of individual characteristics and individual exogenous variables; it leads to a new view of exact aggregation; more importantly it draws attention to structural stability and to the study of factors explaining shifts in the statistical distribution of micro-variables and -parameters. The success of this approach explains why aggregation theory increasingly requires empirical research.

This paper presents some results of a data analysis of Family Expenditure Surveys for the United Kingdom and France. It is shown that these data sets exhibit characteristic features that we call “increasing spread” and “increasing dispersion”. Statistical tools used for analysing the data are discussed. They are based on concepts from non-parametric regression and average derivative estimation. One can show that increasing dispersion supports the weak axiom of revealed preferences of the market demand function. Increasing spread provides empirical evidence for the Law of Demand.

It is not uncommon to see studies of imperfect competition or of industrial organization rest upon questionable foundations such as the hypothesis that inverse market demand is, whenever it is positive, concave or even linear. Assumptions of this sort are not robust (i.e. “additive”) in the sense that they are not usually preserved through aggregation of different sectors that would satisfy them individually. The present paper investigates an alternative specification that is based upon the plausible existence of significant heterogeneities among demanders. It is demonstrated that specific forms of demand heterogeneity tend to stabilize market expenditures. In a partial equilibrium context, sufficient demand heterogeneity is shown to imply existence and unicity of a Cournot oligopoly equilibrium.

This paper is divided into two parts which deal with closely connected issues. The first section of the paper explores the structure of consumer demand systems necessary and sufficient for exact aggregation. The second section addresses a related empirical question: what, if anything, do the restrictions imposed on exactly aggregable demand systems buy the econometrician engaged in estimating integrable consumer demands? In particular, if the objective of an empirical exercise is to estimate the demand systems of individual utility maximizing consumers and only aggregate expenditure information and information on the income and demographic composition of the population are available, then under what conditions can the parameters of the estimated aggregate expenditure system be used to uniquely identify the parameters of the underlying individual demand systems?