OPTIMAL INCOME TAXATION WITH QUASI-LINEAR PREFERENCES REVISITED

With quasi-linear in leisure preferences, closed-form solutions for the marginal tax rates and the marginal utility of consumption under utilitarian and maxi-min objectives depend only on the skill distribution. Bunching induced by binding second-order incentive conditions also depends only on the distribution, but does not affect solutions in the non-bunched range. These are affected if bunching is caused by binding non-negative income constraints. Specific skill distributions are considered and it shown that the pattern of marginal tax rates depend critically on whether or not the skill distribution is truncated at the upper end.Optimal Income Tax, Quasi-Linear Preferences

Can Partial Fiscal Coordination Be Welfare Worsening? A model of tax competition

Most work on tax competition argues that mobile factors tend to be undertaxed except if there is coordination of tax policies. Full coordination is not however always feasible, and as a consequence some measures of partial coordination have been proposed such as minimal witholding taxes on interest income. We show that partial coordination can be in some instances welfare worsening and that then no coordination is to be preferred.tax competition, tax coordination, witholding tax

Notre système de santé est à la croisée des chemins

Notre système de santé - que beaucoup nous envient - est aujourd’hui en danger : comment le réformer pour améliorer son efficience ?

Assurance-maladie : comment adapter les taux de remboursement aux dépenses individuelles de santé?

Nous considérons un modèle d’assurance-maladie dans lequel les agents ne se différencient que par la gravité de la maladie qui les atteint. L’État cherche à maximiser l’espérance d’utilité des assurés et décide en conséquence de rembourser une fraction des dépenses de santé. En l’absence d’aléa moral ex post, suivant lequel la décision individuelle de dépenses de santé est affectée par leur taux de remboursement, celui-ci pourrait être de 100 %. Cependant, avec aléa moral, la gratuité des soins n’est plus de mise. Après une brève présentation du cas d’un taux de remboursement uniforme, nous envisageons d’abord une structure de remboursement à deux taux, le premier s’appliquant en dessous d’un certain seuil de dépenses et le second au-delà du seuil. Nous voulons connaître la valeur relative de ces deux taux de remboursement, ainsi que le montant du seuil. Ensuite nous montrons les caractéristiques d’un remboursement non linéaire, qui nous rapproche un peu plus de la solution de premier rang. Des exemples numériques illustrent les développements analytiques et montrent comment le partage des risques entre bien-portants et malades et la perte d’efficacité due à l’aléa moral varient selon le schéma de remboursement.We consider a health insurance model with heterogeneous agents who only differ in illness severity. The public insurer intends to maximize the expected utility of people insured taking into account the premium paid by them to balance the insurer's budget. Without any ex post moral hazard, the reimbursement rate would be set at 100%. But with moral hazard, the individual decision, as regards medical expenses, varies with this rate. After a short presentation of the single rate case, we consider a two-rate reimbursement structure, with a threshold defining the scope of each rate, the one applying below the threshold and the other taking effect above this cut-off point. We want to determine the relative value of these two rates, as well as the amount of the threshold. Then we characterize a non-linear reimbursement, which is closer to the first-best solution. Some numerical simulations illustrate the analytical developments. They show how the reimbursement structure affects the risk sharing between the healthy and the sick and the efficiency loss caused by moral hazard

Social Insurance and Redistribution

This paper studies optimal linear income taxation and redistributive social insurance when the former has the traditional labor distortion and the latter generates both ex ante and ex post moral hazard. Private insurance is available and individuals differ in labor productivity and in loss probability. We show that government intervention in insurance markets is welfare-improving, and social insurance is generally desirable when there is a negative correlation between labor productivity and loss probability.Social Insurance, Moral Hazard, Redistribution

Assurance-maladie : comment adapter les taux de remboursement aux dépenses individuelles de santé?

We consider a health insurance model with heterogeneous agents who only differ in illness severity. The public insurer intends to maximize the expected utility of people insured taking into account the premium paid by them to balance the insurer's budget. Without any ex post moral hazard, the reimbursement rate would be set at 100%. But with moral hazard, the individual decision, as regards medical expenses, varies with this rate. After a short presentation of the single rate case, we consider a two-rate reimbursement structure, with a threshold defining the scope of each rate, the one applying below the threshold and the other taking effect above this cut-off point. We want to determine the relative value of these two rates, as well as the amount of the threshold. Then we characterize a non-linear reimbursement, which is closer to the first-best solution. Some numerical simulations illustrate the analytical developments. They show how the reimbursement structure affects the risk sharing between the healthy and the sick and the efficiency loss caused by moral hazard. Nous considérons un modèle d’assurance-maladie dans lequel les agents ne se différencient que par la gravité de la maladie qui les atteint. L’État cherche à maximiser l’espérance d’utilité des assurés et décide en conséquence de rembourser une fraction des dépenses de santé. En l’absence d’aléa moral ex post, suivant lequel la décision individuelle de dépenses de santé est affectée par leur taux de remboursement, celui-ci pourrait être de 100 %. Cependant, avec aléa moral, la gratuité des soins n’est plus de mise. Après une brève présentation du cas d’un taux de remboursement uniforme, nous envisageons d’abord une structure de remboursement à deux taux, le premier s’appliquant en dessous d’un certain seuil de dépenses et le second au-delà du seuil. Nous voulons connaître la valeur relative de ces deux taux de remboursement, ainsi que le montant du seuil. Ensuite nous montrons les caractéristiques d’un remboursement non linéaire, qui nous rapproche un peu plus de la solution de premier rang. Des exemples numériques illustrent les développements analytiques et montrent comment le partage des risques entre bien-portants et malades et la perte d’efficacité due à l’aléa moral varient selon le schéma de remboursement.

The Consequences of Overlapping Tax Bases for Redistribution and Public Spending in a Federation

Tax and expenditure policies are studied in a federation with imperfectly mobile households. States implement a linear progressive tax and supply a public good. A vertical fiscal externality, reflecting the effect of state policies on federal revenues, provides an incentive for state taxes to be too progressive. A horizontal fiscal externality causes non-optimal states taxes and expenditures because of the migration effect. The federal government implements its own linear progressive tax and makes transfers to the states. The federal government can nullify both externalities by appropriate fiscal policies, and redistributive taxation can be decentralized to the states.TAXES ; FISCAL POLICY

Subsidies Versus Public Provision of Private Goods as Instruments for Redistribution

The literature on the use of differential commodity taxes/subsidies and that on quantity controls to supplement income taxation have developed separately from each other. The purpose of this paper is to combine these two strands in the standard framework of optimal non-linear income taxation. We start from a simple model in which there are two types of households, the government has access to both subsidy policy and public provision of a good substitutable with leisure, and households can supplement the publicly provided good from the market. We present conditions when optimal policy should involve a mix of these two instruments alongside income taxation or only one of them. We also consider alternative settings, including the extension to many types of households and the inability of households to supplement in-kind transfers.in-kind transfers, subsidies, optimal income tax

Reduced physical activity level and cardiorespiratory fitness in children with chronic diseases

We aimed to compare physical activity level and cardiorespiratory fitness in children with different chronic diseases, such as type 1 diabetes mellitus (T1DM), obesity (OB) and juvenile idiopathic arthritis (JIA), with healthy controls (HC). We performed a cross-sectional study including 209 children: OB: n = 45, T1DM: n = 48, JIA: n = 31, and HC: n = 85. Physical activity level was assessed by accelerometer and cardiorespiratory fitness by a treadmill test. ANOVA, linear regressions and Pearson correlations were used. Children with chronic diseases had reduced total daily physical activity counts (T1DM 497 ± 54cpm, p = 0.003; JIA 518 ± 28, p < 0.001, OB 590 ± 25, p = 0.003) and cardiorespiratory fitness (JIA 39.3 ± 1.7, p = 0.001, OB 41.7 ± 1.2, p = 0.020) compared to HC (668 ± 35cpm; 45.3 ± 0.9mlkg−1 min−1, respectively). Only 60.4% of HC, 51.6% of OB, 38.1% of JIA and 38.5% of T1DM children met the recommended daily 60min of moderate-to-vigorous physical activity. Low cardiorespiratory fitness was associated with female gender and low daily PA. Conclusion: Children with chronic diseases had reduced physical activity and cardiorespiratory fitness. As the benefits of PA on health have been well demonstrated during growth, it should be encouraged in those children to prevent a reduction of cardiorespiratory fitness and the development of comorbiditie

Incentive contracts and the compensation of health care providers

Dans cet article, nous utilisons un modèle d’agence pour étudier comment, dans un contexte d’asymétrie d’informations, la rémunération d’un médecin devrait être reliée au nombre de patients traités. Les médecins n’ont pas tous la même productivité ; les patients qui ont des besoins homogènes peuvent choisir leur médecin, de sorte qu’à l’équilibre, tous les médecins doivent offrir le même niveau de bénéfices nets (amélioration nette de l’état de santé). Le régulateur qui détermine le schéma de rémunération se préoccupe à la fois de la qualité des soins offerts et du niveau des dépenses encourues. Nous montrons que la solution optimale de second rang donne un schéma de rémunération dans lequel la rémunération marginale par patient augmente avec le nombre de patients. Dans une généralisation du modèle, l’amélioration de l’état de santé du patient peut aussi dépendre des services prescrits par le médecin ; nous examinons comment le coût de ces prescriptions devrait être pris en compte dans le schéma de rémunération.In this paper we use a principal-agent model to study how the compensation paid to a physician should be related to the number of his patients. Health care providers are heterogeneous in their productivity ; the homogenous patients are mobile so that their level of net benefits must be equalized across providers. The regulating agency is concerned with both the quality of care and the level of expenditures.We show that the second-best (incomplete information) solution implies that the marginal compensation for a patient increases with the number of patients. In an extension, we also account for the possibility that the benefits (health improvement) provided to a patient depend on prescribed services and study how these should enter the compensation scheme