Equilibrium Policy Simulations with Random Utility Models of Labour Supply

Many microeconometric models of discrete labour supply include alternative-specific constants meant to account for (possibly besides other factors) the density or accessibility of particular types of jobs (e.g. part-time jobs vs. full-time jobs). The most common use of these models is the simulation of tax-transfer reforms. The simulation is usually interpreted as a comparative static exercise, i.e. the comparison of different equilibria induced by different policy regimes. The simulation procedure, however, typically keeps fixed the estimated alternative-specific constants. In this note we argue that this procedure is not consistent with the comparative statics interpretation. Equilibrium means that the number of people willing to work on the various job types must be equal to the number of available jobs. Since the constants reflect the number of jobs and since the number of people willing to work change as a response to the change in tax-transfer regime, it follows that the constants should also change. A structural interpretation of the alternative-specific constants leads to the development of a simulation procedure consistent with the comparative static interpretation. The procedure is illustrated with an empirical example.alternative-specific constants, simulation of tax reforms, labour supply, discrete choice, random utility, equilibrium simulation

Equilibrium policy simulations with random utility models of labour supply

Many microeconometric models of discrete labour supply include alternative-specific constants meant to account for (possibly besides other factors) the density or accessibility of particular types of jobs (e.g. parttime jobs vs. full-time jobs). The most common use of these models is the simulation of tax-transfer reforms. The simulation is usually interpreted as a comparative static exercise, i.e. the comparison of different equilibria induced by different policy regimes. The simulation procedure, however, typically keeps fixed the estimated alternative-specific constants. In this note we argue that this procedure is not consistent with the comparative statics interpretation. Equilibrium means that the number of people willing to work on the various job types must be equal to the number of available jobs. Since the constants reflect the number of jobs and since the number of people willing to work change as a response to the change in tax-transfer regime, it follows that the constants should also change. A structural interpretation of the alternative-specific constants leads to the development of a simulation procedure consistent with the comparative static interpretation. The procedure is illustrated with an empirical example.Random Utility; Discrete Choice; Labour Supply; Simulation of tax reforms; Alternative-specific constants; Equilibrium simulation

Designing Optimal Taxes with a Microeconometric Model of Household Labour Supply

The purpose of this paper is to present an exercise where we identify optimal income tax rules under the constraint of fixed tax revenue. To this end, we estimate a microeconomic model with 78 parameters that capture heterogeneity in consumption-leisure preferences for singles and couples as well as in job opportunities across individuals based on detailed Norwegian household data for 1994. For any given tax rule, the estimated model can be used to simulate the choices made by single individuals and couples. Those choices are therefore generated by preferences and opportunities that vary across the decision units. Differently from what is common in the literature, we do not rely on a priori theoretical optimal taxation results, but instead we identify optimal tax rules – within a class of 6-parameter piece-wise linear rules - by iteratively running the model until a given social welfare function attains its maximum under the constraint of keeping constant the total net tax revenue. We explore a variety of social welfare functions with differing degree of inequality aversion and also two alternative social welfare principles, namely equality of outcome and equality of opportunity. All the social welfare functions turn out to imply an average tax rate lower than the current 1994 one. Moreover, all the optimal rules imply – with respect to the current rule – lower marginal rates on low and/or average income levels and higher marginal rates on relatively high income levels. These results are partially at odds with the tax reforms that took place in many countries during the last decades. While those reforms embodied the idea of lowering average tax rates, the way to implement it has typically consisted in reducing the top marginal rates. Our results instead suggest to lower average tax rates by reducing marginal rates on low and average income levels and increasing marginal rates on very high income levels.Labour supply, optimal taxation, random utility model, microsimulation.

Designing Optimal Taxes With a Microeconometric Model of Household Labour Supply

This paper is concerned with the empirical analyses of optimal taxation, adopting Equality of Outcome (EO) as well as Equality of Opportunity (EOp) as evaluation criteria. The EOp- and EO-criteria provide alternative methods for summarizing the efficiency-equality trade-off in the distribution of individual welfare. We also compare the results depending on whether we use income or money-metric utility as a measure of individual welfare. We estimate micro-econometric models of household labour supply and corresponding individual welfare measures based on 1995 Norwegian data for both married couples and singles. We then use these models to simulate behavioural responses and welfare gains and losses of various constant-revenue four-parameter tax rules, i.e. the tax rules defined by a lump-sum transfer (positive or negative), two marginal tax rates and a “kink point” that produces the same revenue collected with the observed 1995 rules. Using the various EOp- and EO- critera as a basis for evaluating and comparing these tax rules, EOp- and EO-optimal tax rules are identified.Optimal Taxation, Labour Supply, Microeconometric Models

Preference Heterogeneity in Relation to Museum Services

The prevailing trends in the management of European museums underline the importance of additional museum services in fostering and encouraging the optimisation of cultural assets, while facilitating the collection of the necessary resources for conservation. The paper considers the case of the archaeological site of Paestum (Salerno) and presents an analysis of individual preferences in relation to specific policies of cultural heritage management, each characterised by the supply of different museum services. Since the diversity of these services can prompt different individual preferences, the analysis allows for heterogeneity of parameters among individuals.cultural goods; heterogeneous preferences; stated preference data; conjoint analysis; mixed logit;

Accounting for Family Background when Designing Optimal Income Taxes: A Microeconometric Simulation Analysis

The purpose of this paper is to introduce and adopt a generalised version of Roemer's (1998) Equality of Opportunity (EOp) framework, which we call extended EOp, for analysing second-best optimal income taxation. Unlike the pure EOp criterion of Roemer (1998) the extended EOp criterion allows for alternative weighting profiles in the treatment of income differentials between as well as within types when types are defined by circumstances that are beyond people's control. This study uses parental education as a measure of exogenous circumstances. An empirical microeconometric model of labour supply in Italy is employed to simulate and identify income tax-transfer rules that are optimal according to the extended EOp criterion. We look for second-best optimality, i.e. the tax-transfer rules are not allowed to depend on family background, they only depend on income: family background is taken indirectly into account. The rules are defined by a universal (not individualized) lump-sum transfer (positive or negative) and by one or two marginal tax rates. A rather striking result of the analysis is that the optimal tax-transfer rule turns out to be a universal lump-sum tax (with marginal tax rates equal to zero), under Roemer's pure EOp criterion as well as under the generalised EOp criterion with moderate degrees of aversion to within-type inequality. A higher degree of within-type inequality aversion instead produces EOp-optimal rules with positive marginal tax rates. When the EOp-version of the Gini welfare function is adopted, the optimal tax rule turns out to be close to the actual 1993 Italian tax system, if not for the important difference of prescribing a universal lump-sum positive transfer of 3,500,000 ITL (=1807 Euros), which has no comparable counterpart in the actual system. On the other hand, when using the conventional equality of outcome (EO) criterion, the pure lump-sum tax always turns out to be optimal, at least with respect to the classes of two- and three-parameter rules. We also compute optimal rules under the additional constraint that universal lump-sum taxes are not feasible. Overall, the results do not conform to the perhaps common expectation that the EO criterion is more supportive of "interventionist" (redistributive) policies than an extended EOp approach.equality of opportunity, equality of outcome, labour supply, optimal income taxation

Using a Microeconometric Model of Household Labour Supply to Design Optimal Income Taxes

The purpose of this paper is to present an exercise where we identify optimal income tax rules according to various social welfare criteria, keeping fixed the total net tax revenue. Empirical applications of optimal taxation theory have typically adopted analytical expressions for the optimal taxes and then imputed numerical values to their parameters by using "calibration" procedures or previous econometric estimates. Besides the restrictiveness of the assumptions needed to obtain analytical solutions to the optimal taxation problem, a shortcoming of that procedure is the possible inconsistency between the theoretical assumptions and the assumptions implicit in the empirical evidence. In this paper we follow a different procedure, based on a computational approach to the optimal taxation problem. To this end, we estimate a microeconomic model with 78 parameters that capture heterogeneity in consumption-leisure preferences for singles and couples as well as in job opportunities across individuals based on detailed Norwegian household data for 1994. For any given tax rule, the estimated model can be used to simulate the labour supply choices made by single individuals and couples. Those choices are therefore generated by preferences and opportunities that vary across the decision units. We then identify optimal tax rules – within a class of 9-parameter piece-wise linear rules - by iteratively running the model until a given social welfare function attains its maximum under the constraint of keeping constant the total net tax revenue. The parameters to be determined are an exemption level, four marginal tax rates, three "kink points" and a lump sum transfer that can be positive (benefit) or negative (tax). We explore a variety of social welfare functions with differing degree of inequality aversion. All the social welfare functions imply monotonically increasing marginal tax rates. When compared with the current (1994) tax systems, the optimal rules imply a lower average tax rate. Moreover, all the optimal rules imply – with respect to the current rule – lower marginal rates on low and/or average income levels and higher marginal rates on relatively high income levels. These results are partially at odds with the tax reforms that took place in many countries during the last decades. While those reforms embodied the idea of lowering average tax rates, the way to implement it has typically consisted in reducing the top marginal rates. Our results instead suggest to lower average tax rates by reducing marginal rates on low and average income levels and increasing marginal rates on very high income levels.Labour supply; optimal taxation; random utility model; microsimulation

Evaluating Alternative Representations of the Choice Sets in Models of Labour Supply

During the last two decades, the discrete-choice modelling of labour supply decisions has become increasingly popular, starting with Aaberge et al. (1995) and van Soest (1995). Within the literature adopting this approach there are however two potentially important issues that are worthwhile analyzing in their implications and that up to know have not been given the attention that they might deserve. A first issue concerns the procedure by which the discrete alternative are chosen. For example Van Soest (1995) chooses (non probabilistically) a set of fixed points identical for every individual. This is by far the most widely adopted method. By contrast, Aaberge et al. (1995) adopt a sampling procedure and also assume that the choice set may differ across the households. A second issue concerns the availability of the alternatives. Most authors assume all the values of hours-of-work within some range [0, H] are equally available. At the other extreme, some authors assume only two or three alternatives (e.g. non-participation, part-time and full-time) are available for everyone. Aaberge et al. (1995) assume instead that not all the hour opportunities are equally available to everyone; they specify a probability density function of opportunities for each individual and the discrete choice set used in the estimation is built by sampling from that individual-specific density function. In this paper we explore by simulation the implications of - the procedure used to build the choice set (fixed alternatives vs sampled alternatives) - accounting vs not accounting for a different availability of alternatives. The way the choice set is represented seems to have little impact on the fitting of observed values, but a more significant and important impact on the prediction of policy effects.Microeconometric Models, Discrete Choice, Choice Set, Labour Supply, Tax Reforms.