Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  longitudinal data
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
We present a novel study concerning the attitudes of road transport enterprises towards a broad application of telematics in operational management in road transportation. The study aims to assess telematics application in road transport and its changes over time while showing the factors most likely to determine the systems’ use. Unobserved categories defined in the technology acceptance model (TAM) are adjusted to measure perceived usefulness, perceived ease of use, and attitudes toward using telematics systems by road transport managers. The study is based on 323 transport enterprises analyzed in two waves in 2020 and 2021. The use of two different time points is motivated by an observed increase in the digitalization of transport documents caused by the COVID-19 pandemic. The empirical findings support the TAM’s usefulness in evaluating IT in transport business management. The findings also reveal that the significantly increased telematics use in 2020 was observed while it was endured. The results are checked for robustness and used for simulations. The study compares managers’ behaviors over time and simulates the effect of individual (observed) variables on unobserved TAM categories.
EN
This study aims to analyse the relationship between world-largest car manufacturers' environmental, social and governance (ESG) disclosures and their financial and market-based performance. For this purpose, the models of choice were panel data considering ten years. A set of independent control variables and ESG score or subsets of the ESG score were investigated against the dependent measures of a firm’s financial (ROA) and market-based (Tobin’s Q) performance. The paper's novelty is the industry-specific perspective and results that are scarce and indicate a mixed influence of the ESG subsets. The results obtained by regression analysis underline a non-significant positive relationship between ESG and ROA, meaning ESG activities are valued less than expected. Interestingly, the market's valuation, which Tobin's Q should capture, has presented some significant influence. That implies that investors value ESG performance in the long term, which is particularly relevant information for decision-makers in the automotive industry.
PL
Niniejsze badanie ma na celu analizę związku między ujawnianymi przez największych światowych producentów samochodów informacjami dotyczącymi środowiska, społeczeństwa i ładu korporacyjnego (ESG) a ich wynikami finansowymi i rynkowymi. W tym celu wybrano modele danych panelowych obejmujące dziesięć lat. Zestaw zmiennych kontrolnych niezależnych i wynik ESG lub podzbiory wyniku ESG zostały zbadane pod kątem zależnych miar wyników finansowych (ROA) i rynkowych (Q Tobina) firmy. Nowością w artykule jest perspektywa branżowa i wyniki, które są rzadkie i wskazują na mieszany wpływ podzbiorów ESG. Wyniki uzyskane za pomocą analizy regresji podkreślają nieistotny dodatni związek między ESG a ROA, co oznacza, że działania ESG są wyceniane niżej niż oczekiwano. Co ciekawe, wycena rynkowa, którą powinno odzwierciedlać Q Tobina, wykazała pewien znaczący wpływ. Oznacza to, że inwestorzy cenią wyniki ESG w perspektywie długoterminowej, co jest szczególnie istotną informacją dla decydentów w branży motoryzacyjnej.
EN
Although the occurrence of road accidents and the number of road accident casualties in almost all Polish voivodeships has decreased over the last few years, the rate of this change varies considerably from region to region. To provide a better understanding of such a tendency, panel data regression models are proposed to conduct this pilot research which evaluates the relative performance of Polish regions in terms of their road traffic safety. Panel data are multi-dimensional data which involve measurements over time. In the research, a voivodeship is a unit analysed at a group level, whereas a year is a unit analysed at a time level. A two-way error component regression model has been applied to survey the impact of regressors, the group effects, and time effects on a dependent variable. The analysis has been conducted using data acquired from the Statistics Poland Local Data Bank website, as well as from the General Directorate for National Roads and Motorways. The panel data from 16 regions in Poland and the 2012–2018 period have been investigated. The examined models refer to road traffic safety indices defined based on the following characteristics: the number of road accidents, the number road fatalities, and the number of people injured. The results of all the three models indicate a negative effect as regards the GDP per capita, (car) motorisation rate, the indicator of government expenditure for current maintenance of national roads, and the road length per capita. A positive association has been found between the truck motorisation rate and the indicator of local government expenditure on roads. The impact of the region’s urbanisation indicators on road safety is ambiguous as, on the one hand, its increase causes a reduction in the road accident and accident injury indices, but, on the other hand, it produces a rise in the accident fatality index. In the models, the significance of time effects has been identified; a decreasing time trend suggests a general improvement in road safety from year to year. Most of the group effects have turned out to be highly significant. However, the effects differ as regards both the road accident and the accident injury indices in magnitude and direction.
EN
The assessment of fetal size and the accurate estimation of gestational age are of crucial importance for proper pregnancy management. The information is almost exclusively based on ultrasound measurements of fetal biometric parameters and the means for evaluating these measurements are age-related reference charts (centile charts) allowing interpretation of obtained fetal measurement in comparison with the expected average measurement in the reference population. The construction of such reference charts requires an appropriate statistical methodology. The most frequent method for the construction of fetal reference charts from cross-sectional data is the parametric approach with fractional polynomials regression functions for the mean and standard deviation of each fetal measurement. This article suggests how this method can be extended to longitudinal data using fractional polynomials in linear mixed effect regression. The presented approach includes maximum likelihood estimation for fitting first- and second-order fractional polynomial models, and multimodel inference using Akaike's information criterion and related tools as a suitable strategy for model selection. Finally, an example of the suggested approach is presented.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.