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- Modelling Deprivation of the 50-plus Population of the Czech Republic Based on the Share SurveyIvana MaláIn the paper, two composite indicators – the indices of material and social deprivation – are analyzed based on the Survey of Health, Ageing and Retirement in Europe exploring the population aged 50 and over. A finite normal mixture model for the social deprivation index and a finite mixture of Bernoulli and normal distributions are used to model the distribution of the indices of deprivation for the Czech Republic in 2013. Applying a logistic regression model, the parameter of Bernoulli distribution is supposed to be dependent on explanatory variables. In terms of material deprivation, the situation in the Czech Republic is comparable to other European countries, the social deprivation index, showing, however, higher values.KeywordsMaterial deprivation, social deprivation, composite indicators, normal mixed model, logistic regression
- Use of Logistic Regression for Understanding and Prediction of Customer Churn in TelecommunicationsJan Manďák, Jana HančlováCustomer churn, loss of customers due to switch to another service provider or non-renewal of commitment,
is very common in highly competitive and saturated markets such as telecommunications. Predictive models
need to be implemented to identify customers who are at risk of churning and also to discover the key drivers
of churn. The aim of this paper is to use demographic and service usage variables to estimate logistic regression
model to predict customer churn in European Telecommunications provider and to find the factors influencing
customer churn. An interesting findings came out of the estimated model – younger customers who are shorter
time with company, who use mobile data and sms more than traditional calls, having occasional problem
with paying bills, with students account and ending contract in the near future are typical representatives
of customers who tend to leave the company.
An interaction terms added as explanatory variables showed that effect of usage of data and voice vary
depending on the year of birth. The quality of the logistic regression model was assessed by Hosmer-Lemeshow test and pseudo R squared measures. An independent testing data set was further used to evaluate the predictive ability of the model by computation of performance metrics such as the area under the ROC curve (AUC), sensitivity and precision. The resulting model was able to catch 94.8% of customers who in fact left the company. Quality of the model was confirmed also by high value of AUC metric equal to 0.9759. Logistic regression represents a very useful tool in prediction of customer churn not only thanks to its interpretability, but also for its predictive power.KeywordsCustomer churn, telecommunications, predictive analytics, logistic regression, sensitivity - Application of Hierarchical Cluster Analysis in Educational Research: Distinguishing between Transmissive and Constructivist Oriented Mathematics TeachersJanka Medová, Jana Bakusová
Special questionnaire containing two sets of items related to teachers’ beliefs and current pedagogies was completed by 30 mathematics in-service teachers from 26 different lower secondary schools in Slovakia. Their responses were analysed by means of hierarchical cluster analysis. The clustering method was chosen by the correlation coefficient between Euclidean and dendrogram-predicted distances. Cluster analysis grouped the items of this questionnaire into four clusters, describing the following aspects: (1) discipline and classroom culture; (2) pedagogies and problem solving; (3) applications of mathematics and students’ activity during the lesson; and (4) teachers’ attitudes towards students’ individuality and mathematics. Teachers were grouped into two clusters. Based on the differences between responses we consider one cluster of teachers as transmissiveoriented and the second one as constructivist-oriented.
KeywordsHierarchical cluster analysis, mathematics education, teachers’ beliefs, instructional approaches - Searching for Correlations Between CO2 Emissions and Selected Economic ParametersLadislav Rozenský, Pavla Vrabcová, Miroslav Hájek, Tereza Veselá, Petr HukalThe Emission Trading Scheme is one of the economic instruments of environmental policy and it is used to achieve the goals of reducing greenhouse gas emissions. The Emission Trading Scheme is a common instrument of the European Union, which is mandatory for all member countries. The aim of this paper is to assess the effectiveness of the greenhouse gas emissions trading system in the Czech Republic as one of the important instruments of environmental policy. The presented research model shows that greenhouse gas emissions were only minimally affected by the GDP index level and movement in the monitored time period. The model also shows that the most significant impact on the amount of greenhouse gas production in the given time period was the consumption of renewable energy and the consumption of fossil fuels. By contrast, the price of emission allowances on the market had a minimal effect on the production of greenhouse gases.KeywordsEconomic instruments, emission trading scheme, emission allowances, renewable energy
- The Informativeness of the Technical Conversion Factor for the Price Ratio of Processing LivestockKris Boudt, Hong Anh LuuThe technical conversion factor (TCF) is a survey-based estimate of the percentage of carcass weight obtained per unit of live weight. Practitioners and researchers have used it to predict the corresponding price ratio (PR). We use both in-sample regressions and out-of-sample forecasting analysis to test the validity of this approach in case of predicting the price effects of processing livestock in Europe. By regressing the PR on the inverse value of the corresponding TCF for a large panel of European countries and animal types, we find a significant positive relation between these variables, which also has economic value in terms of improving out-of-sample forecasting precision. This result is shown to be robust to animal type, year, and country fixed effects. The TCF therefore has predictive value about the corresponding PR.KeywordsAgriculture, carcass weight, live weight, producer price, pass-through effect
- Boomerang Effect of Quality Control on the Compilation of Financial Accounts and Flow of Funds: the Experience of Banco de PortugalSusana Santos, António AgostinhoFinancial Accounts are fundamental to monitor financial stability by quantifying the impact of financial decisions of a host of economic agents. In Portugal, the compilation of these statistics is a responsibility of Banco de Portugal. One of the main purposes of the Statistics Department of Banco de Portugal is to ensure this statistical production with high quality standards, aiming at fully meeting user’s needs, by developing a wide set of quality control procedures. In this context, Banco de Portugal developed a multidisciplinary team with experts from financial accounts and from the different underlying primary statistics. Within this format, that can be viewed as a “boomerang effect”, all team members are co-responsible for producing national financial accounts, on a bottom-up approach, thus improving both the quality of these statistics, as well as the quality of primary statistics. This is the result of a systematic iterative process of data cross-check and reconciliation which may represent an opportunity to validate the soundness of microdata, on a top-down approach.KeywordsQuality control, financial accounts, multidisciplinary team, data cross-check, flow of funds
- The article presents a new method of normalization – normalization with respect to pattern (or pattern
normalization in short). It has properties expected for this type of transformation: preserves skewness, kurtosis
and the Pearson correlation coefficients. Although pattern normalization uses only observations from the current
unit of time, it can be used in dynamic research. An additional advantage of new normalization is the ability
to reflect different analysis environments. The effects of pattern normalization are illustrated by an empirical example. Indicators monitoring the implementation of the Europe 2020 Strategy are used. Normalizations are carried out for two reference groups: the entire EU and countries that joined the EU in 2004. The results for two years are compared. The example of Poland shows that the “dynamic image” of the country is affected by the use of pattern normalization itself as well as by the choice of the environment. In this context pattern normalization is similar to dynamic standardization, and different than dynamic scaling.KeywordsNormalization, standardization, transformation of variables - Empirically Supported Methodological Critique of Double Entry in Dyadic Data AnalysisImre Dobos, Andrea Gelei
Analyzing dyadic phenomena (e.g. trust, power, and satisfaction) gains importance not only in sociology and
psychology, but also in economics and management. The aim of the paper is to examine the mathematical
foundation of Dyadic Data Analysis (DDA). On one hand, we critique the database development of DDA
for exchangeable cases, and develop an algorithm for transforming such a data set into distinguishable cases.
On the other hand, we question the usefulness of a widely used data development technique of DDA, the so-called double entry. We reason that this technique does not necessarily lead to additional information. In contrast, it might lead to information losses. We develop approximations for correlations and regression models of DDA. These are also empirically tested using a database of 89 dyads. The obtained results back our theoretical reasoning, most of the approximations give satisfying results. This support our main proposition that mathematical foundation of DDA needs further research.KeywordsCorrelational analysis, regression analysis, dyadic data analysis, double entry technique - At its centenary, Czech official statistics is facing several challenges. Some are well known, others are emerging
in a new and rapidly changing world. The Czech Statistical Office and other parts of Czech official statistics
have a good record of coping and are well prepared. The time ahead, however, may be harder than the past. The acceleration of change in the world at large emphasises several challenges in front of official statistics, see relevance and education, as well as a number of technical developments like big data and changing means of communication. The main issue, however, will probably be the need to protect the independence of official statistics from vested interests in a world where automatisms replace specific decisions and where statistics are used as controls.KeywordsCzech official statistics, challenges, dangers