Count Data Modelling and Tourism Demand

This thesis consists of four papers concerning modelling of count data and tourism demand. For three of the papers the focus is on the integer-valued autoregressive moving average model class (INARMA), and especially on the INAR(1) model. The fourth paper studies the interaction between households' choice of number of leisure trips and number of overnight stays within a bivariate count data modelling framework. Paper[I] extends the basic INAR(1) model to enable more flexible and realistic empirical economic applications. The model is generalized by relaxing some of the model’s basic independence assumptions. Results are given in terms of first and second conditional and unconditional order moments. Extensions to general INAR(p), time-varying, multivariate and threshold models are also considered. Estimation by conditional least squares and generalized method of moments techniques is feasible. Monte Carlo simulations for two of the extended models indicate reasonable estimation and testing properties. An illustration based on the number of Swedish mechanical paper and pulp mills is considered. Paper[II] considers the robustness of a conventional Dickey-Fuller (DF) test for the testing of a unit root in the INAR(1) model. Finite sample distributions for a model with Poisson distributed disturbance terms are obtained by Monte Carlo simulation. These distributions are wider than those of AR(1) models with normal distributed error terms. As the drift and sample size, respectively, increase the distributions appear to tend to t(T-2) and standard normal distributions. The main results are summarized by an approximating equation that also enables calculation of critical values for any sample and drift size. Paper[III] utilizes the INAR(1) model to model the day-to-day movements in the number of guest nights in hotels. By cross-sectional and temporal aggregation an INARMA(1,1) model for monthly data is obtained. The approach enables easy interpretation and econometric modelling of the parameters, in terms of daily mean check-in and check-out probability. Empirically approaches accounting for seasonality by dummies and using differenced series, as well as forecasting, are studied for a series of Norwegian guest nights in Swedish hotels. In a forecast evaluation the improvements by introducing economic variables is minute. Paper[IV] empirically studies household's joint choice of the number of leisure trips and the total night to stay on these trips. The paper introduces a bivariate count hurdle model to account for the relative high frequencies of zeros. A truncated bivariate mixed Poisson lognormal distribution, allowing for both positive as well as negative correlation between the count variables, is utilized. Inflation techniques are used to account for clustering of leisure time to weekends. Simulated maximum likelihood is used as estimation method. A small policy study indicates that households substitute trips for nights as the travel costs increase.Time series; Count data; INARMA; Unit root; Aggregation; Forecasting; Tourism; Truncation; Inflation; Simulated maximum likelihood; Bivariate hurdle model.

Forecasting based on Very Small Samples and Additional Non-Sample Information

Generalized method of moments estimation and forecasting is introduced for very small samples when additional non-sample information is available. Small simulation experiments are conducted for the linear model with errors-in-variables and for a Poisson regression model. Two empirical illustrations are included. One is based on Ukrainian imports and the other on private schools in a Swedish county.Generalized method of moments; additional information; forecasting; Ukrainian imports; private schools

The Impact of Stock Market Jumps on Time-Varying Return Correlations: Empirical Evidence from the Baltic Countries

In this paper we study the impact of market jumps on the time varying return correlations between stock market indices in the Baltic countries. An EARJI-EGARCH model facilitating direct modelling of the time varying return correlations is introduced. The empirical results indicate that there is a quite large number of identi…ed jumps in the emerging Baltic stock markets. The main …nding is that isolated market jumps in one of the markets generally have no or small e¤ects on the time-varying correlations. In contrast, simultaneous jumps of equal sign increase the average correlation, in some cases with as much as 100 percent.Correlated jumps; contagion

Uncertainty in the Generic Versus Brand Name Prescription Decision

This paper analyzes the impact of uncertainty concerning product quality of generic drugs on the substitution behavior of prescribing physicians. It is shown that uncertainty about the generic drug quality gives the physician a value of waiting for more information before switching to the generic version. In addition, it is shown that reducing the approval requirements for generic drugs, thereby increasing uncertainty about quality, may discourage physicians from prescribing such drugs. A small empirical study supports the theoretical findings and indicate that uncertainty about the quality of generic drugs do affect physician prescription behavior.Pharmaceutical industry; uncertainty; real options

Does the Open Limit Order Book Reveal Information About Short-run Stock Price Movements?

This paper empirically tests whether an open limit order book contains information about future short-run stock price movements. To account for the discrete nature of price changes, the integer-valued autoregressive model of order one is utilized. A model transformation has an advantage over conventional count data approaches since it handles negative integer-valued price changes. The empirical results reveal that measures capturing offered quantities of a share at the best bid- and ask-price reveal more information about future short-run price movements than measures capturing the quantities offered at prices below and above. Imbalance and changes in offered quantities at prices below and above the best bid- and ask-price do, however, have a small and significant effect on future price changes. The results also indicate that the value of order book information is short-term.Negative integer-valued data; time series; INAR; finance; stock price; open limit order book

Comparing Centralized and Decentralized Banking: A Study of the Risk-Return Profiles of Banks

This paper studies the risk-return profile of centralized and decentralized banks. We address the conditions that favor a particular lending regime while acknowledging the effects on lending and returns caused by the course of the business cycle. To analyze these issues, we develop a model which incorporates two stylized facts; (i) banks in which lending decisions are decentralized tend to have a lower cost associated with screening potential borrowers and (ii) decentralized decision-making may generate inefficient outcomes because of lack of coordination. Simulations are used to compare the two banking regimes. Among the results, it is found that asymmetric markets (in terms of the proportion of high ability entrepreneurs) tend to favor centralized banking while decentralized banks seem better at lending in the wake of an economic downturn (high probability of a recession). In addition, we find that even though a bank group where decisions are decentralized may end up with a portfolio of loans which is (relatively) poorly diversified between regions, the ability to effectively screen potential borrowers may nevertheless give a decentralized bank a lower overall risk in the lending portfolio than when decisions are centralized.lending; screening; business cycle; portfolio diversification; risk; organization; simulations

Why Do Politicians Implement Central Bank Independence Reforms?

It is something of a puzzle that politicians around the world have chosen to give up power to independent central banks, thereby reducing their possibilities to fine-tune the economy. In this paper the determinants of central bank independence (CBI) reforms are studied using a new data set on the possible event of such reforms in 119 countries. According to the data, as much as 81 countries had implemented CBI-reforms during the study period. The results indicate, moreover, that policymakers are more likely to delegate power to independent central banks when the foreign debt is relatively high. In non-OECD countries, the likelihood of a CBI-reform also seems to increase when policymakers face a high probability of getting replaced.Institutional reforms; inflation; time-inconsistency; political stability; probit

Identi�cation of jumps in �financial price series

The paper outlines and tests, by means of Monte-Carlo simulations, a simple strategy of using existing non-parametric tests for jumps at the daily frequency to identify jumps at higher sampling frequencies. The suggested strategy allow for identi�cation of the number of jumps and jump times during a day, as well as, the size and direction (negative or positive) of the jumps. The method is of importance in order to facilitate detailed empirical studies concerning, for example, causes for jumps in fi�nancial price series at �ner levels than the daily. The Monte Carlo study reveals that the strategy works reasonably well, particular for lower jump intensities. An application of the studied strategy on the Handelsbanken stock is provided

Identi�cation of jumps in �financial price series

The paper outlines and tests, by means of Monte-Carlo simulations, a simple strategy of using existing non-parametric tests for jumps at the daily frequency to identify jumps at higher sampling frequencies. The suggested strategy allow for identi�cation of the number of jumps and jump times during a day, as well as, the size and direction (negative or positive) of the jumps. The method is of importance in order to facilitate detailed empirical studies concerning, for example, causes for jumps in fi�nancial price series at �ner levels than the daily. The Monte Carlo study reveals that the strategy works reasonably well, particular for lower jump intensities. An application of the studied strategy on the Handelsbanken stock is provided