Documents Roventini, Andrea 15 results

"In this work we develop an agent-based model where hysteresis in major macroeconomic variables (e.g. GDP, productivity, unemployment) emerges out of the decentralized interactions of heterogeneous firms and workers. Building upon the model in Dosi et al. (2016, 2017), we specify an endogenous process of accumulation of workers' skills and a state-dependent process of entry, studying their hysteretic impacts. Indeed, hysteresis is ubiquitous. However, this is not due to market imperfections, but rather to the very functioning of decentralised economies characterised by coordination externalities and dynamic increasing returns. So, contrary to the insider-outsider hypothesis (Blanchard and Summers, 1986), the model does not support the findings that rigid industrial relations may foster hysteretic behaviour in aggregate unemployment. On the contrary, in line with the recent discussion in Ball et al. (2014), this contribution provides evidence that during severe downturns, and thus declining aggregate demand, phenomena like lower investment and innovation rates, skills deterioration, and declining entry dynamics are better candidates to explain long-run unemployment spells and lower output growth. In that, more rigid labour markets dampen hysteretic dynamics by supporting aggregate demand, thus making the economy more resilient."

"This paper is meant to analyse the effects of labour market structural reforms by means of an agent-based model. Building on Dosi et al. (2016b) we introduce a policy regime change characterized by a set of structural reforms on the labour market, keeping constant the structure of the capital- and consumption-good markets. Confirming a recent IMF report (Jaumotte and Buitron, 2015), the model shows how labour market structural reforms reducing workers' bargaining power and compressing wages tend to increase (i) unemployment, (ii) functional income inequality, and (iii) personal income inequality. We further undertake a global sensitivity analysis on key variables and parameters which confirms the robustness of our findings."

"In this work we investigate the interrelations among technology, output and employment in the different states of the U.S. economy (recessions vs. expansions). More precisely, we estimate different threshold vector autoregression (TVAR) models with TFP, hours, and GDP, employing the latter as threshold variable, and we assess the ensuing generalized impulse responses of GDP and hours as to TFP shocks. We find that positive productivity shocks, while spurring GDP growth, display a negative effect on hours worked at least on impact, independently of the state of the economy. In the 1957-2011 period, the effects of productivity shocks on employment are abundantly negative in downturns, but they are not significantly different from zero in good times. However, the impact of TFP shocks in different business cycle regimes depends on the chosen sample: after the mid eighties (1984-2011), productivity shocks increase hours during recessions. Finally, we express and test some conjectures that might have caused the changes in the responses in different time periods."

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Wages are an element of cost crucially affecting the competitiveness of individual firms. But the wage bill is also a crucial element of aggregate demand. Hence it could be that more “flexible” and fluid labour markets, while allowing for faster inter-firm reallocation of labour, may also render the whole economic system more fragile, more prone to recession, more volatile. In this work we investigate some conditions under which such a conjecture applies. The paper presents an agentbased model that investigates the effects of two “archetypes of capitalism”, in terms of regimes of labour governance – defined by the mechanisms of wage determination, firing, labour protection and productivity gains sharing – upon (i) labour market regularities and (ii) macroeconomic dynamics (long-term rates of growth, GDP fluctuations, unemployment rates, inequality, etc..). The model is built upon the “Keynes meets Schumpeter” family of models (Dosi et al., 2010), explicitly incorporating different microfounded labour market regimes. Our results show that seemingly more rigid labour markets and labour relations are conducive to coordination successes with higher and smoother growth."

"This paper extends the endogenous-growth agent-based model in Fagiolo and Dosi (2003) to study the financegrowth nexus. We explore industries where firms produce a homogeneous good using existing technologies, perform R&D activities to introduce new techniques, and imitate the most productive practices. Unlike the original model, we assume that both exploration and imitation require resources provided by banks, which pool agent savings and finance new projects via loans. We find that banking activity has a positive impact on growth. However, excessive financialization can hamper growth. In- deed, we find a significant and robust inverted-U shaped relation between financial depth and growth. Overall, our results stress the fundamental (and still poorly understood) role played by innovation in the finance-growth nexus."

"We analyze the individual and macroeconomic impacts of heterogeneous expectations and action rules within an agent-based model populated by heterogeneous, interacting firms. Agents have to cope with a complex evolving economy characterized by deep uncertainty resulting from technical change, imperfect information and coordination hurdles. In these circumstances, we find that neither individual nor macroeconomic dynamics improve when agents replace myopic expectations with less naïve learning rules. In fact, more sophisticated, e.g. recursive least squares (RLS) expectations produce less accurate individual forecasts and also considerably worsen the performance of the economy. Finally, we experiment with agents that adjust simply to technological shocks, and we show that individual and aggregate performances dramatically degrade. Our results suggest that fast and frugal robust heuristics are not a second-best option: rather they are “rational” in macroeconomic environments with heterogeneous, interacting agents and changing “fundamentals”."

"In this work we develop a set of labour market and fiscal policy experiments upon the labour and credit augmented “Schumpeter meeting Keynes” agent-based model. The labour market is declined under two institutional variants, the “Fordist” and the “Competitive” set-ups meant to capture the historical transition from the Fordist toward the post “Thatcher- Reagan” period. Inside these two regimes, we study the different effects of supply-side active labour market policies (ALMPs) vs. demand-management passive labour market ones (PLMPs). In particular, we analyse the effects of ALMPs aimed at promoting job search, and at providing training to unemployed people. Next, we compare the effects of these policies with unemployment benefits simply meant to sustain income and therefore aggregate demand. Considering the burden of unemployment benefits in terms of public budget, we link such provision with the objectives of the European Stability and Growth Pact. Our results show that (i) an appropriate level of skills is not enough to sustain growth when workers face adverse labour demand; (ii) supply-side policies are not able to reverse the perverse interaction between flexibility and austerity; (iii) PLMPs outperform ALMPs in reducing unemployment and workers' skills deterioration; and (iv) demand-management policies are better suited to mitigate inequality and to improve and sustain long-run growth."

"Climate change is one of the most daunting challenges human kind has ever faced. In the paper, we provide a survey of the micro and macro economics of climate change from a complexity science perspective and we discuss the challenges ahead for this line of research. We identify four areas of the literature where complex system models have already produced valuable insights: (i) coalition formation and climate negotiations, (ii) macroeconomic impacts of climate-related events, (iii) energy markets and (iv) diffusion of climatefriendly technologies. On each of these issues, accounting for heterogeneity, interactions and disequilibrium dynamics provides a complementary and novel perspective to the one of standard equilibrium models. Furthermore, it highlights the potential economic benefits of mitigation and adaptation policies and the risk of under-estimating systemic climate change-related risks."

"In this work, we employ an agent-based integrated assessment model to study the likelihood of transition to green, sustainable growth in presence of climate damages. The model comprises heterogeneous fossil-fuel and renewable plants, capital- and consumption-good firms and a climate box linking greenhouse gasses emission to temperature dynamics and microeconomic climate shocks affecting labour productivity and energy demand of firms. Simulation results show that the economy possesses two statistical equilibria: a carbon-intensive lock-in and a sustainable growth path characterized by better macroeconomic performances. Once climate damages are accounted for, the likelihood of a green transition depends on the damage function employed. In particular, aggregate and quadratic damage functions overlook the impact of climate change on the transition to sustainability; to the contrary, more realistic micro-level damages are found to deeply influence the chances of a transition. Finally, we run a series of policy experiments on carbon (fossil fuel) taxes and green subsidies. We find that the effectiveness of such market-based instruments depends on the different channels climate change affects the economy through, and complementary policies might be required to avoid carbon-intensive lock-ins."