Working Papers
2023
February 24, 2023
Weighted Median Inflation Around the World: A Measure of Core Inflation
Description: The standard measure of core or underlying inflation is the inflation rate excluding food and energy prices. This paper constructs an alternative measure, the weighted median inflation rate, for 38 advanced and emerging economies using subclass level disaggretion of the CPI over 1990-2021, and compares the properties of this measure to those of standard core. For quarterly data, we find that the weighted median is less volatile than standard core, more closely related to economic slack, and more closely related to headline inflation over the next year. The weighted median also has a drawback: in most countries, it has a lower average level than headline inflation. We therefore also consider a measure of core inflation that eliminates this bias, which is based on the percentile of sectoral inflation rates that matches the sample average of headline CPI inflation.
February 24, 2023
Differential Effects of Macroprudential Policy
Description: We explore the differential effects of lender-based macroprudential policies on new mortgage borrowing for households of different income using a comprehensive dataset that links macroprudential policy actions with household survey data for European Union countries. The main results suggest that higher-income households on average experience a larger reduction in mortgage loan size than lower-income households when regulation targeting total lenders’ assets tightens. In contrast, lower-income households on average experience a larger reduction in mortgage loan size than higher-income households when regulation targeting lenders’ capital requirements tightens. We also provide evidence of the different channels through which the differential effects operate.
February 24, 2023
Assessing the Impact of Supply Disruptions on the Global Pandemic Recovery
Description: We estimate the role of (pre-Ukraine war) supply disruptions in constraining the Covid-19 pandemic recovery, for several advanced economies and emerging markets, and globally. We rely on two approaches. In the first approach, we use sign-restricted Vector Auto Regressions (SVAR) to identify supply and demand shocks in manufacturing, based on the co-movement of surveys on new orders and suppliers’ delivery times. The effects of these shocks on industrial production and GDP are recovered through a combination of local projection methods and the input-output framework in Acemoglu et al. (2016). In the second approach, we use the IMF’s G20 model to gauge the importance of supply shocks in jointly driving activity and inflation surprises. We find that supply disruptions subtracted between 0.5 and 1.2 percent from global value added during the global recovery in 2021, while also adding about 1 percent to global core inflation that same year.
February 24, 2023
Surrogate Data Models: Interpreting Large-scale Machine Learning Crisis Prediction Models
Description: Machine learning models are becoming increasingly important in the prediction of economic crises. The models, however, use datasets comprising a large number of predictors (features) which impairs model interpretability and their ability to provide adequate guidance in the design of crisis prevention and mitigation policies. This paper introduces surrogate data models as dimensionality reduction tools in large-scale crisis prediction models. The appropriateness of this approach is assessed by their application to large-scale crisis prediction models developed at the IMF. The results are consistent with economic intuition and validate the use of surrogates as interpretability tools.
February 24, 2023
AI and Macroeconomic Modeling: Deep Reinforcement Learning in an RBC model
Description: This study seeks to construct a basic reinforcement learning-based AI-macroeconomic simulator. We use a deep RL (DRL) approach (DDPG) in an RBC macroeconomic model. We set up two learning scenarios, one of which is deterministic without the technological shock and the other is stochastic. The objective of the deterministic environment is to compare the learning agent's behavior to a deterministic steady-state scenario. We demonstrate that in both deterministic and stochastic scenarios, the agent's choices are close to their optimal value. We also present cases of unstable learning behaviours. This AI-macro model may be enhanced in future research by adding additional variables or sectors to the model or by incorporating different DRL algorithms.
February 24, 2023
Global Supply Chain Disruptions: Challenges for Inflation and Monetary Policy in Sub-Saharan Africa
Description: The Covid-19 pandemic has led to a large disruption of global supply chains. This paper studies the implications of supply chain disruptions for inflation and monetary policy in sub-Saharan Africa. Increases in supply chain pressures have had a sizeable impact on headline, food, and tradable inflation for a panel of 29 sub-Saharan African countries from 2000 to 2022. Our findings suggest that central banks can stabilize inflation and output more efficiently by monitoring global supply chains and adjusting the monetary policy stance before the disruptions have fully passed through into all inflation components. The gains from monitoring supply chain disruptions are particularly large for open economies which tend to experience outsized second-round effects on the prices of non-tradable goods and services.
February 24, 2023
Guaranteeing Trade in a Severe Crisis: Cash Collateral over Bank Guarantees
Description: Banks guarantee international trade through letters of credit. This paper analyzes what happens to trade when the critical role of banks as trade guarantors is compromised. Using the case of the Greek capital controls in 2015, the events around which led to a massive loss of confidence in the domestic banking system, we show that firms whose operations were more dependent on domestic banks suffered a steep decline in imports and, subsequently, exports. This operated through letters of credit, which during the capital controls period had to be backed by firms’ own cash collateral rather than the bank guarantee. As a result, cash-poor firms imported relatively less. Public intervention to guarantee transactions is shown to help mitigate some of the decline in imports.
February 17, 2023
Political Institutions and Output Collapses
Description: Major output collapses are costly and frequent in the developing world. Using cross-country data, we classify five-year periods using a two-dimensional state space based on growth regimes and political institutions. We then model the joint evolution of output growth and political institutions as a finite state Markov chain, and study how countries move between states. We find that growth is more likely to be sustained under democracy than under autocracy; output collapses are more persistent under autocracy; and stagnation under autocracy can give way to outright collapse. Democratic countries appear to be more resilient.
February 17, 2023
Personal Income Taxes in the Middle East and North Africa: Prospects and Possibilities
Description: Personal income taxes (PITs) play little or no role in the Middle East and North Africa, often yielding less than 2 percent of GDP in revenue—with the exception of few North African countries. This paper examines how PITs have evolved in recent decades, and what they might look like in the next 20 years. Top marginal tax rates on labor and business income of individuals have declined substantially, a trend that mirrors reductions in advanced and developing economies. Taxation of passive capital income has changed very little, and the revenue intake from this source remains low throughout the region (less than 1 percent of GDP on average and concentrated in oil-importing non-fragile states). Social security contributions (SSC) have increased in importance in nearly all MENA countries, and some countries have introduced additional payroll taxes. The combination of reduced marginal tax rates, light taxation of income from capital and business activities, and increase of SSC, have resulted in income tax systems that create disincentives to work and incentives for informality, and contribute little to government revenue and income redistribution. Given differences in economic and political structures, demographics, and starting points, the path to PIT/SSC reforms will vary across the region. Countries with relatively mature PIT/SSC systems, where revenue performance has improved in the past two decades, will increasingly need to balance the revenue and equity objectives against effciency objectives (in particular labor market incentives and infromality). Countries with no PITs will have to weigh whether a consumption tax/SSC system that mimic a flat tax on labor income is sufficient to diversify revenue away from oil and whether to adopt PITs to address rising income and wealth inequality. Finally, fragile states, who face more political volatility and weaker fiscal institutions, will have to focus on simplicity of tax design and collection to be able to raise revenue from PITs.
February 17, 2023
Bubble Detective: City-Level Analysis of House Price Cycles
Description: This paper investigates house price dynamics at high frequency using city-level observations during the period 1994-2022 in Lithuania. We employ multiple time series-based econometric procedures to examine whether real house prices and house price-to-rent ratios exhibit explosive behavior. According to these recursive right-tailed test results, we reject the null hypothesis of no-bubble and find evidence for long and multiple periods of explosive behavior in the real estate market in all major cities during the sample period. While the size of bubbles varies across cities, especially when we use the house price-to-rent ratio, there is clearly a similar boom-bust pattern. Large house price corrections can in turn have adverse effects on economic performance and financial stability, as experienced during the global financial crisis and other episodes in history.