Juan A. Rojas

Modelling the impact of aging on social security expenditures

In this paper we survey the features of different approaches available in the literature used to study the effects of the aging of the population on Social Security expenditures. We comment on the weaknesses and strengths of each of them, and perform a quantitative analysis by comparing the results they imply in the particular case of the Spanish economy. Finally, we highlight some elements of the modelling strategies on which more evidence is needed for a correct evaluation of the problem at hand.

Fiscal Policy, Structural Reforms and External Imbalances: A Quantitative Evaluation for Spain

This paper builds a large overlapping generations model of a small open economy featuring imperfect competition in the labor and product markets to understand i) which were the main determinants of the large expansionary phase experienced in Spain from the mid-1990s until the arrival of the global financial crisis in 2007-2008, ii) what role fiscal policy and structural reforms could have played to avoid the build-up of large external imbalance over this period, and iii) how these policies could affect the recovery of economic activity in Spain after the crisis. Our results indicate that falling interest rates and demographic changes were the main drivers of the Spanish expansionary phase. As for the macroeconomic behavior of the Spanish economy after the crisis, our results suggest that a front-loading in fiscal consolidation together with structural reforms that eliminate distortions in the goods and labor markets could make the recovery of economic activity in Spain more successful.

Social Security Reform with Imperfect Substitution between Less and More Experienced Workers

In this paper we study the quantitative properties of a policy reform aimed at funding the pension system in the standard model economy with perfect substitution across workers with different experience levels and a model economy where this substitutability is imperfect. With compulsory retirement, the welfare gains for young cohorts are underestimated in the standard model economy with perfect substitution as compared to the imperfect substitution case. However these additional welfare gains displayed in the imperfect substitution case come at the cost of higher welfare losses for the generations living at the time of the policy reform, due to the fall in the experience premium that follows after the elimination of social security. When the policy reform consists of the elimination of both social security and compulsory retirement, we find that in the standard model the status quo problem disappears. However, such policy change is not able to solve the status quo problem when less and more experienced workers are imperfect substitutes because the fall in the experience premium is more pronounced, providing a rationale for the lack of political support in favour of pension reform in the Spanish economy.

Solving Portfolio Problems with the Smolyak-Parameterized Expectations Algorithm

We propose a new numerical method to solve stochastic models that combines the parameterized expectations (PEA) and the Smolyak algorithms. This method is especially convenient to address problems with occasionally binding constraints (a feature inherited from PEA) and/or a large number of state variables (a feature inherited from Smolyak), i.e. DSGE models that incorporate portfolio problems and incomplete markets. We describe the proposed Smolyak-PEA algorithm in the context of a one-country stochastic neoclassical growth model and compare its accuracy with that of a standard PEA collocation algorithm. Despite estimating fewer parameters, the former is able to reach the high accuracy levels of the latter. We further illustrate the working of this algorithm in a two-country neoclassical model with incomplete markets and portfolio choice. Again, the Smolyak-PEA algorithm approximates the solution of the problem with a high degree of accuracy. Finally, we show how this algorithm can efficiently incorporate both occasionally binding constraints and a partial information approach.

Implicit public debt thresholds: an empirical exercise for the case of Spain

We extend previous work that combines the Value at Risk approach with estimation of the correlation pattern of the macroeconomic determinants of public debt dynamics by means of Vector Auto Regressions (VARs). These estimated models are used to compute the probability that the public debt ratio exceeds a given threshold, by means of MonteCarlo simulations. We apply this methodology to Spanish data and compute time-series probabilities to analyse the possible correlation with market risk assessment, measured by the spread over the German bond. Taking into account the high correlation between the probability of crossing a pre-specifi ed debt threshold and the spread, we go a step further and ask what would be the threshold that maximises the correlation between the two variables. The aim of this exercise is to gauge the implicit debt threshold or «prudent debt level» that is most consistent with market expectations as measured by the sovereign yield spread. The level thus obtained is consistent with the medium-term debt-to-GDP ratio anchor of 60% of GDP.

Skewed Credit and Growth Dynamics after the Global Financial Crisis

A large empirical literature finds that financial development is beneficial for economic growth, although some recent evidence suggests otherwise. The paper contributes to the finance–growth literature by examining the role of credit growth skewness and long-run growth. Earlier literature found that credit growth skewness is negatively associated with economic growth. It revisits this relationship using a large and recent panel dataset that encompasses Organisation for Economic Co-operation and Development economies and the impact of the global financial crisis. While the results reconfirm an association between credit skewness and growth, the relationship is more nuanced than previously thought. It finds that the beneficial effects from lower skewness—systemic financial risks—were evident only prior to 2000. The findings help explain why boom–bust dynamics were positively associated with economic growth in emerging markets in the past and why the growth of advanced economies has been sluggish since the global financial crisis.

Debt Stocks Meet Gross Financing Needs: A Flow Perspective into Sustainability

It is well known that no single metric can provide reliable cross-country risk assessments of debt sustainability. While approaches to understanding sustainability have traditionally relied heavily on stock metrics, a consensus is emerging that debt sustainability should be linked to both stock and flow features of underlying public debt. This paper informs this debate by analysing the ability of gross financing needs, the preferred flow metric in current debt sustainability analyses by official institutions, to provide additional information to that provided by standard stock metrics of a sovereign’s likelihood of distress. Our main contribution is to document a significant negative effect from changes in gross financing needs when debt stocks are high. These results support the intuition that countries can sustain very large debt stocks if these do not generate unmanageable flow needs. Additionally, we show that sovereign roll-over needs are a critical element driving this effect. Given the role of official lending in taming the dynamics of this component, our findings also inform the literature on the role of official lending in crises resolution.