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Robust Student estimator
Hlavinka, Radek ; Friml, Dominik (referee) ; Dokoupil, Jakub (advisor)
This Master's thesis deals with Bayesian approach to robust parameter estimation for ARX models. Robustness is achieved by assuming the measurement noise to be generated by Student-t distribution. The asumption of Student-t noise renders the model's posterior intractable and requires utilization of approximation techniques. This thesis considers algorithms using Gibbs sampler and Variational approximation and compares them with Ordinary Least Squares. The algorithms are compared based on their Maximum Likelihood estimation. It is shown that approaches assuming the Student-t noise perform better in simulation. The results from data acquired from physical system are however similar for all algorithms considered.
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System Priors for Econometric Time Series
Andrle, Michal ; Plašil, Miroslav
This paper introduces “system priors” into Bayesian analysis of econometric time series and provides a simple and illustrative application. Unlike priors on individual parameters, system priors offer a simple and efficient way of formulating well-defined and economically meaningful priors about model properties that determine the overall behavior of the model. The generality of system priors is illustrated using an AR(2) process with a prior that its dynamics comes mostly from business-cycle frequencies.
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Iterated Multi-Step Forecasting with Model Coefficients Changing Across Iterations
Franta, Michal
Iterated multi-step forecasts are usually constructed assuming the same model in each forecasting iteration. In this paper, the model coefficients are allowed to change across forecasting iterations according to the in-sample prediction performance at a particular forecasting horizon. The technique can thus be viewed as a combination of iterated and direct forecasting. The superior point and density forecasting performance of this approach is demonstrated on a standard medium-scale vector autoregression employing variables used in the Smets and Wouters (2007) model of the US economy. The estimation of the model and forecasting are carried out in a Bayesian way on data covering the period 1959Q1–2016Q1.
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Raising the minimum wage and the Austrian apriorism
Panýr, Jakub ; Špecián, Petr (advisor) ; Brožová, Dagmar (referee)
This thesis deals with a problem of a relationship between minimum wage and potential consequent unemployment. While solving it, I am trying to connect apriorism of the misesian branch of the Austrian school and a Bayesian approach. It will enable us to correct our subjective belief in certain hypothesis with regard to the new facts which may appear. Sentences of the Austrian school about a certain positive relationship between raising the minimum wage and unemployment of unskilled workers, based on claiming about a synthetic a priori character of these sentences, seems as not so convincing, after confrontation with the Bayesian epistemology and facts from other disciplines. Then I am trying to show, that refusing of a quantification of unique events seems to be wrong and not coherent with callings of the Austrian school for "realistic" foundaitons. The Austrian school may according to these findings give up its claim about unchallengeable certainty of its theories, and complement it with a healthy dose of this Bayesian approach.
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In the Quest of Measuring the Financial Cycle
Plašil, Miroslav ; Konečný, Tomáš ; Seidler, Jakub ; Hlaváč, Petr
The recent financial crisis has demonstrated the importance of the linkages between the financial sector and the real economy. This paper sets out to develop two complementary methods for assessing the position of the economy in the financial cycle in order to identify emerging imbalances in timely manner. First, we construct a composite indicator using variables representing risk perceptions in the financial sector and calibrate this indicator to capture the credit losses the Czech banking sector experienced during the recent crisis. Second, we focus on the transitions of loans from one risk category to another, which allows us to capture the financial cycle from the perspective of the debt-paying ability of non-financial corporations. Both financial cycle measures can be used by policy makers for a wide range of policy decisions, including that on the setting of the countercyclical capital buffer.
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Rare Shocks vs. Non-linearities: What Drives Extreme Events in the Economy? Some Empirical Evidence
Franta, Michal
A small-scale vector autoregression (VAR) is used to shed some light on the roles of extreme shocks and non-linearities during stress events observed in the economy. The model focuses on the link between credit/financial markets and the real economy and is estimated on US quarterly data for the period 1984–2013. Extreme shocks are accounted for by assuming t-distributed reduced-form shocks. Non-linearity is allowed by the possibility of regime switch in the shock propagation mechanism. Strong evidence for fat tails in error distributions is found. Moreover, the results suggest that accounting for extreme shocks rather than explicit modeling of non-linearity contributes to the explanatory power of the model. Finally, it is shown that the accuracy of density forecasts improves if non-linearities and shock distributions with fat tails are considered.
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Habit Formation in Consumption: A Meta-Analysis
Havránek, Tomáš ; Rusnák, Marek ; Sokolova, Anna
We examine 567 estimates of habit formation from 69 studies published in peer-reviewed journals. In contrast to previous results for most fields of empirical economics, we find no publication bias in the literature. The median estimated strength of habit formation equals 0.4, but the estimates vary widely both within and across studies. We use Bayesian model averaging to assign a pattern to this variance while taking into account model uncertainty. Studies using micro data report consistently smaller estimates than macro studies: 0.1 vs. 0.6 on average. The difference remains large when we control for 21 other study aspects, such as data frequency, geographical coverage, variable definition, estimation approach, and publication characteristics. We also find that estimates of external habit formation tend to be substantially larger than those of internal habits, that evidence for habits weakens when researchers use higher data frequencies, and that estimates differ systematically across countries.
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Bank Competition and Financial Stability: Much Ado about Nothing?
Havránek, Tomáš ; Žigraiová, Diana
The theoretical literature gives conflicting predictions on how bank competition should affect financial stability, and dozens of researchers have attempted to evaluate the relationship empirically. We collect 598 estimates of the competition-stability nexus reported in 31 studies and analyze the literature using meta-analysis methods. We control for 35 aspects of study design and employ Bayesian model averaging to tackle the resulting model uncertainty. Our findings suggest that the definition of financial stability and bank competition used by researchers influences their results in a systematic way. The choice of data, estimation methodology, and control variables also affects the reported coefficient. We find evidence for moderate publication bias. Taken together, the estimates reported in the literature suggest little interplay between competition and stability, even when corrected for publication bias and potential misspecifications.
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Cross-Country Heterogeneity in Intertemporal Substitution
Havránek, Tomáš ; Horváth, Roman ; Iršová, Zuzana ; Rusnák, Marek
We collect 2,735 estimates of the elasticity of intertemporal substitution in consumption from 169 published studies that cover 104 countries during different time periods. The estimates vary substantially from country to country, even after controlling for 30 aspects of study design. Our results suggest that income and asset market participation are the most effective factors in explaining the heterogeneity: households in rich countries and countries with high stock market participation substitute a larger fraction of consumption intertemporally in response to changes in expected asset returns. Micro-level studies that focus on sub-samples of rich households or asset holders also find systematically larger values of the elasticity.
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International Reserves: Facing Model Uncertainty
Benecká, Soňa ; Komárek, Luboš
The abundant literature on the competing motives for holding international reserves stresses different factors, giving rise to a problem called model uncertainty. In this paper we search for the most important determinants of reserve holdings using data for 104 countries in 1999–2010 and evaluate their importance using Bayesian model averaging (BMA). We enrich the ongoing empirical discussion by examining the role of financial globalization and monetary policy and by introducing new variables and searching for alternatives to the traditional ones. The results confirm that trade openness and the broad-money-to-GDP ratio are the key determinants with a positive link to the level of reserves. On the other hand, financial development seems to lower the need for reserves.
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