Estimating rating transition probabilites with missing data

In this article we provide a rigorous treatment of one of the central statistical issues of credit risk management. GivenK-1 rating categories, the rating of a corporate bond over a certain horizon may either stay the same or change to one of the remainingK-2 categories; in addition, it is usually the case that the rating of some bonds is withdrawn during the time interval considered in the analysis. When estimating transition probabilities, we have thus to consider aK-th category, called withdrawal, which contains (partially) missing data. We show how maximum likelihood estimation can be performed in this setup; whereas in discrete time our solution gives rigorous support to a solution often used in applications, in continuous time the maximum likelihood estimator of the transition matrix computed by means of the EM algorithm represents a significant improvement over existing methods.     

Testing for autocorrelation in non-stationary dynamic systems of equations

Using Monte Carlo methods, the properties of systemwise generalizations of the Breusch-Godfrey test for autocorrelated errors are studied in integrated cointegrated systems of equations. Our analysis, regarding the size of the test, reveals that the corrected LR tests have been shown to perform satisfactorily even in cases when the exogenous variables follow a unit root process, whilst the commonly used TR2 test behaves badly even in single equations. All tests perform badly, however, when the number of equations increases and the exogenous variables are highly autocorrelated.     

Demographic crisis: The impact of the Bangladesh civil war (1971) on births and deaths in a rural area of Bangladesh

Summary In Matlab Bazaar Thana the Cholera Research Laboratory has registered the births, deaths and migrations in a population of approximately 125,000 since 1966. Although this rural area was not the scene of any significant armed encounters, striking changes in birth and death rates were registered during and after the conflict. Birth rates did not change during the relatively brief period of the civil war, but a small decline was registered for one year after the war. Fertility rates which had been declining slightly and irregularly in the pre-war baseline period may have increased slightly during the war and fell substantially in all age groups in the year following the war. The crude death rate, which rose by 37 per cent during the war, was a very sensitive reflection of the administrative and economic problems. Overall infant mortality rose by only 15 per cent over pre-war levels because all of the increase was observed in the post-neo-natal component, which traditionally accounts for less than one-third of the total infant mortality in Bangladesh. Children and older adults accounted for the majority of excess deaths which were largely attributed to acute diarrhoeas and other gastro-intestinal causes. The death rate at ages 1-4 rose by 43 per cent and at ages 5-9 soared to 208 per cent above pre-war baseline rates. All increases in age-specific mortality rates fell to baseline levels during the year following the war, except the 5-9-year age group, in which rates continued to be high largely because of deaths due to dysentery.     

The Robustness of High Danish National Happiness: A Temporal Cross-Country Analysis of Population Subgroups

Denmark’s top position in various rankings of country happiness is well-documented. This study goes beyond the national average comparisons and investigates whether Denmark’s top position is also found when we disaggregate data in line with social categories often used within the social sciences. The central measure is the empirical probability that a given population subgroup in Denmark has significantly higher happiness compared to another country’s similar subgroup in a given year. All five rounds of the European Social Survey are used but only the sixteen countries that were surveyed in each of the five rounds are included in this study. The results show that Denmark’s position at the top of the happiness scale is also robust when we look at population subgroups, but not in the sense that Denmark dominates all countries for all years. Instead, a modified version of robustness is necessary; Denmark very often has significantly higher happiness levels than in other countries, only sometimes has the same happiness levels as in other countries, very rarely is it dominated by other countries, and finally it is never dominated by other countries in all 5 years for a given subpopulation characteristic. This conclusion is quite insensitive to the applied SWB measure and the applied significance level.

     

Factor screening in nonregular two-level designs based on projection-based variable selection

In this paper, we focus on the problem of factor screening in nonregular two-level designs through gradually reducing the number of possible sets of active factors. We are particularly concerned with situations when three or four factors are active. Our proposed method works through examining fits of projection models, where variable selection techniques are used to reduce the number of terms. To examine the reliability of the methods in combination with such techniques, a panel of models consisting of three or four active factors with data generated from the 12-run and the 20-run Plackett–Burman (PB) design is used. The dependence of the procedure on the amount of noise, the number of active factors and the number of experimental factors is also investigated. For designs with few runs such as the 12-run PB design, variable selection should be done with care and default procedures in computer software may not be reliable to which we suggest improvements. A real example is included to show how we propose factor screening can be done in practice.     

Choosing summary statistics by least angle regression for approximate Bayesian computation

Bayesian statistical inference relies on the posterior distribution. Depending on the model, the posterior can be more or less difficult to derive. In recent years, there has been a lot of interest in complex settings where the likelihood is analytically intractable. In such situations, approximate Bayesian computation (ABC) provides an attractive way of carrying out Bayesian inference. For obtaining reliable posterior estimates however, it is important to keep the approximation errors small in ABC. The choice of an appropriate set of summary statistics plays a crucial role in this effort. Here, we report the development of a new algorithm that is based on least angle regression for choosing summary statistics. In two population genetic examples, the performance of the new algorithm is better than a previously proposed approach that uses partial least squares.     

How the acculturation of Baba Nyonya community affects Malacca food identity?

ABSTRACT

The migration of the Chinese community to Malacca in the 16th century has enabled the process of cross culturing and culinary acculturation, producing a unique mixture of Baba Nyonya food. Even though Baba Nyonya food is pretty much has been localised (Malay), its Chinese representation cannot be denied. This study aims to assess how the acculturation of the Baba Nyonya community affects Malacca food identity. A quantitative methodology is employed in this study. This study classifies Baba Nyonya food acculturation through (1) types of food; (2) methods of cooking; (3) ingredients; and (4) eating decorum. From the regression analysis, this study found that Baba Nyonya cultural polarity explains significant variation in the formation of Malacca food identity. This study then elaborates on the importance of Baba Nyonya food in Malacca destination branding.     

Securitized citizens: Islamophobia,racism and the 7/7 London bombings

The London bombings of 7 July 2005 were a major event shaping the relationship between Muslims and non‐Muslims in Britain. In this paper we introduce the idea of ‘securitized citizens’ to analyse the changing relationship between British Muslims and wider British society in response to this and similar events. Through an analysis of qualitative interviews with Muslims and non‐Muslims of a variety of ethnic backgrounds in the areas where the London bombers lived in West Yorkshire we examine the popular perceptions of non‐Muslims and Muslims’ experiences. We show how processes of securitization and racialization have interacted with Islamophobic discourses and identifications, as well as the experiences of Muslims in West Yorkshire after the attacks.     

Influential factors and performance of logistics outsourcing practices: an evidence of malaysian companies

Despite the growing trend of logistics outsourcing, there are very limited sources of literature on logistics outsourcing, especially in determining the relationship between factors influencing outsourcing and the extent of logistics outsourcing practices. In this study, we tap into the field of strategic management to help clarify the mechanisms underlying the links between factors influencing, logistics outsourcing practices and outsourcing performance. A model based on the resource based view illustrates the hypothetical connections among these variables. The data gathered from the survey were analysed using SmartPLS software. A response rate of 21 % out of the 486 firms selected was achieved and fixed as the empirical data for this study. The results of this study provide support that superior performance is correlated to the resources of the firm. The analysis shows that lack of human and physical asset capabilities, as well as transaction uncertainty influence the extent of different logistics outsourcing practices. The four logistics outsourcing practices under study were found to have a positive relationship with logistics outsourcing performance, particularly strategic focus. This study shows that although theoretically firms aim at cost reduction by employing a logistics outsourcing strategy but not proven in this study because the financial benefit was only positively contributed by one of the four logistics outsourcing practices under study. Besides that, the results from this study also support that most firms outsource their non-core activities of the logistics practices to respond to the transaction uncertainty that their business experiences.     

Multi-ethnic school environment from the school leader’s perspective: challenges and approaches to improve multi-cultural competency among teachers in Malaysia

This study aims to identify the challenges and approaches to improve a multicultural competency among teachers in multi-ethnic schools environment based on school leaders’ perspective. Data collection method used in this study is qualitative method. A total of nine school leaders from the states of Kedah, Penang, and Perak were included in the interview session. The results of this study show that the challenges faced by teachers in practicing the multicultural competency are lack of experience toward cultural diversity. A late exposure to cultural diversity makes it difficult for teachers to accept and adapt in a multi-ethnic school environment. The approaches suggested by school leaders to improve the multicultural competency are as follows: (1) Courses on cultural diversity should be organized to enhance the knowledge about cultural diversity; (2) the development of more open and better policy for education system in Malaysia in order to prepare teachers with a higher multicultural competency for teaching students from diverse ethnic and cultural groups; (3) an early exposure to cultural diversity in order to increase the multicultural competency, especially during teaching practicum.