Les modèles DSGE au FMI : applications et développements récents

Researchers in economic policy-making institutions have invested much energy in developing a new generation of macroeconomic models that rely on more solid microeconomic foundations. This article briefly describes applications of two such models. The Global Economy Model (GEM) is a quarterly model comprising a large set of nominal and real rigidities that enable users to generate realistic short-term dynamics. As the model rests on the representative-agent paradigm, its main weakness is that its fundamental theoretical structure does not provide a very realistic characterization of tax-policy effects. By contrast, the Global Fiscal Model (GFM) – an annual model – uses a nested-generation framework, and has been explicitly designed to study the longer-term consequences of alternative tax policies.Les chercheurs dans des institutions ayant pour responsabilité de formuler des politiques économiques ont déployé un effort significatif pour développer une nouvelle génération de modèles macro-économiques reposant sur des bases micro-économiques plus rigoureuses. L’article fournit une présentation résumée des applications de deux de ces modèles. Le Modèle Economique Global (Global Economy Model, GEM) est un modèle trimestriel qui comporte un grand assortiment des rigidités nominales et réelles qui permettent de générer des dynamiques réalistes à court terme. Comme ce modèle se repose sur le paradigme de l’agent représentatif, sa faiblesse principale est que sa structure théorique de base ne fournit pas une caractérisation très réaliste des effets de la politique fiscale. En revanche, le Modèle Fiscal Global (Global Fiscal Model, GFM), qui est un modèle annuel, adopte un cadre à générations imbriquées et a été conçu explicitement pour étudier les conséquences à plus long terme de politiques fiscales alternatives.Laxton Douglas, Karam Philippe, Botman Dennis. Les modèles DSGE au FMI : applications et développements récents. In: Économie & prévision, n°183-184, 2008-2-3. pp. 175-198

Options for Fiscal Consolidation in the United Kingdom

This paper examines the macroeconomic effects of different timing and composition of fiscal adjustment in the United Kingdom using the IMF’s Global Fiscal Model. Early consolidation dampens aggregate demand in the short term, but increases output in the long term as smaller primary surpluses are needed as a result of lower interest payments. Reducing government transfers or current government spending provides larger gains than increasing taxes, in particular compared to raising corporate or personal income taxes. We show that these conclusions are robust under alternative behavioral assumptions and parameterizations. A reduction in global saving would make early consolidation more urgent from both cyclical and long-term perspectives. Finally, we show that tax reform aimed at increasing incentives to save could provide support to fiscal consolidation measures.Fiscal consolidation;Fiscal reforms;Government expenditures;Public debt;Savings promotion;Tax increases;Tax reforms;income taxes, tax reform, fiscal adjustment, corporate income taxes, taxation, government spending, fiscal policy, capital accumulation, personal income taxes, aggregate demand, tax rates, fiscal rules, fiscal policies, corporate income taxation, fiscal model, tax system, payroll tax, interest payments, government budget, government budget constraint, higher interest rates, government expenditure, budget constraint, corporate income tax, fiscal balance, tax increase, average tax rate, taxes on labor, fiscal variables, payroll taxes, public finances, tax returns, fiscal issues, wage taxes, tax distortions, fiscal position, fiscal affairs, sales tax, fiscal solvency, fiscal stimulus, capital stock, fiscal policy framework, tax rates on capital, corporate taxes, fiscal structure, foreign fiscal policies, tax burden, labor taxes, income tax rates, personal income tax, tax liabilities, fiscal reform, efficient tax system, fiscal affairs department, debt service, tax cuts, fiscal framework

Strategies for fiscal consolidation in Japan

Japan's key fiscal challenge is to put public finances on a more sustainable footing. This paper investigates the macroeconomic implications of alternative fiscal strategies for Japan using the IMF's Global Fiscal Model. The results suggest that (i) an adjustment package that achieves primary balance through lower social transfers and government spending and a higher VAT is the most viable option and has a smaller negative impact on growth than other fiscal measures; (ii) achieving primary balance is not sufficient to stabilize the net debt ratio; (iii) prefunding future aging costs provides greater long-term benefits compared with less front-loaded strategies; (iv) tax reform involving shifting from corporate taxation to consumption taxation could mitigate the short-term output losses associated with fiscal consolidation; (v) the spillovers to the rest of the world from consolidation in Japan are positive in the medium term, but modest.Fiscal adjustment Aging Debt sustainability Tax reform Spill-over effects GFM

Tax Reform and Debt Sustainability in Germany

In 2005, the German government announced a far-reaching fiscal adjustment program. This paper uses the IMF’s Global Fiscal Model to study its impact and explores options for addressing long-term pressures from population aging. The growth effects of the planned VAT increase are likely modest, largely owing to the stimulating effect of other tax reductions. The reform will improve the long-term debt path but achieving fiscal sustainability requires further adjustment over the medium term. An additional package of expenditure restraint, entitlement reform, and tax-base broadening compares favorably to other adjustment options. Spillover effects to trading partners of these policies are modest.Aging;Debt sustainability;Tax reforms;Value added tax;Economic models;taxation, tax reform, fiscal adjustment, tax base, fiscal policy, payroll taxes, vat rate, tax measures, government spending, corporate income taxation, fiscal model, fiscal sustainability, tax policy, consumption tax, tax increases, tax system, fiscal consolidation, tax rates, corporate income tax, expenditure cuts, fiscal pressures, direct taxation, indirect taxes, tax reform proposals, indirect tax, income taxes, tax reductions, public debt, tax exemptions, aggregate demand, personal income tax, efficient tax system, indirect taxation, fiscal policies, vat revenue, consumption taxes, budget constraint, fiscal deficits, fiscal adjustment package, fiscal deficit, direct taxes, income tax rates, effects of taxation, fiscal reaction function, personal income taxes, sales tax, expenditure ratios, tax distortions, expenditure restraint, cuts in government spending, fiscal reform, fiscal affairs department, tax bases, fiscal reaction, fiscal difficulties, payroll tax, fiscal implications, fiscal impulse, expenditure policy, direct tax, tax burden, fiscal affairs, fiscal structure, fiscal balance, fiscal issues, fiscal improvement, fiscal scenario, marginal tax rates, deficit reduction, capital stock, fiscal variables, primary expenditure, fiscal developments, current account deficit

Using the AKAR3-EV biosensor to assess Sch9p- and PKA-signalling in budding yeast

Budding yeast uses the TORC1-Sch9p and cAMP-PKA signalling pathways to regulate adaptations to changing nutrient environments. Dynamic and single-cell measurements of the activity of these cascades will improve our understanding of the cellular adaptation of yeast. Here, we employed the AKAR3-EV biosensor developed for mammalian cells to measure the cellular phosphorylation status determined by Sch9p and PKA activity in budding yeast. Using various mutant strains and inhibitors, we show that AKAR3-EV measures the Sch9p- and PKA-dependent phosphorylation status in intact yeast cells. At the single-cell level, we found that the phosphorylation responses are homogenous for glucose, sucrose, and fructose, but heterogeneous for mannose. Cells that start to grow after a transition to mannose correspond to higher normalized Förster resonance energy transfer (FRET) levels, in line with the involvement of Sch9p and PKA pathways to stimulate growth-related processes. The Sch9p and PKA pathways have a relatively high affinity for glucose (K0.5 of 0.24 mM) under glucose-derepressed conditions. Lastly, steady-state FRET levels of AKAR3-EV seem to be independent of growth rates, suggesting that Sch9p- and PKA-dependent phosphorylation activities are transient responses to nutrient transitions. We believe that the AKAR3-EV sensor is an excellent addition to the biosensor arsenal for illuminating cellular adaptation in single yeast cells.</p

An Improved ATP FRET Sensor for Yeast Shows Heterogeneity during Nutrient Transitions

Adenosine 5-triphosphate (ATP) is the main free energy carrier in metabolism. In budding yeast, shifts to glucose-rich conditions cause dynamic changes in ATP levels, but it is unclear how heterogeneous these dynamics are at a single-cell level. Furthermore, pH also changes and affects readout of fluorescence-based biosensors for single-cell measurements. To measure ATP changes reliably in single yeast cells, we developed yAT1.03, an adapted version of the AT1.03 ATP biosensor, that is pH-insensitive. We show that pregrowth conditions largely affect ATP dynamics during transitions. Moreover, single-cell analyses showed a large variety in ATP responses, which implies large differences of glycolytic startup between individual cells. We found three clusters of dynamic responses, and we show that a small subpopulation of wild-type cells reached an imbalanced state during glycolytic startup, characterized by low ATP levels. These results confirm the need for new tools to study dynamic responses of individual cells in dynamic environments