Search results for "regression model"
showing 10 items of 53 documents
Assessing mental health therapeutic communities functioning
2019
Empirical and clinical evidence shows that therapeutic communities produce changes in people’s mental health and well-being. Treatment in communities has effects on improving interpersonal relationships, acceptance among members, ability to recognize other people’s feelings, symptomatology, life satisfaction and self-esteem. This paper aims to investigate which factors can explain the treatment effectiveness, measured by an index which incorporates the point of view of the communities staff members, by means of a beta regression model with random intercept. The results show the influence of some organizational dimension as well as staff roles, providing a meaningful insights into the functi…
A penalized approach to covariate selection through quantile regression coefficient models
2019
The coefficients of a quantile regression model are one-to-one functions of the order of the quantile. In standard quantile regression (QR), different quantiles are estimated one at a time. Another possibility is to model the coefficient functions parametrically, an approach that is referred to as quantile regression coefficients modeling (QRCM). Compared with standard QR, the QRCM approach facilitates estimation, inference and interpretation of the results, and generates more efficient estimators. We designed a penalized method that can address the selection of covariates in this particular modelling framework. Unlike standard penalized quantile regression estimators, in which model selec…
Marginal hazard ratio estimates in joint frailty models for heart failure trials
2019
Abstract This work is motivated by clinical trials in chronic heart failure disease, where treatment has effects both on morbidity (assessed as recurrent non‐fatal hospitalisations) and on mortality (assessed as cardiovascular death, CV death). Recently, a joint frailty proportional hazards model has been proposed for these kind of efficacy outcomes to account for a potential association between the risk rates for hospital admissions and CV death. However, more often clinical trial results are presented by treatment effect estimates that have been derived from marginal proportional hazards models, that is, a Cox model for mortality and an Andersen–Gill model for recurrent hospitalisations. …
Sparse relative risk regression models
2020
Summary Clinical studies where patients are routinely screened for many genomic features are becoming more routine. In principle, this holds the promise of being able to find genomic signatures for a particular disease. In particular, cancer survival is thought to be closely linked to the genomic constitution of the tumor. Discovering such signatures will be useful in the diagnosis of the patient, may be used for treatment decisions and, perhaps, even the development of new treatments. However, genomic data are typically noisy and high-dimensional, not rarely outstripping the number of patients included in the study. Regularized survival models have been proposed to deal with such scenarios…
Relationship Between Extreme Rainfall and Surface Temperature in Sicily (Italy)
2018
The study of the relationship between extreme rainfall events and surface temperature represents an important issue in hydrology and meteorology and it could be of capital importance for evaluating the effect of global warming on future precipitation. Various approaches have been tested across different parts of the world, and, in many cases, it has been observed an intensification of precipitation with increasing temperature consistently with the thermodynamic Clausius-Clapeyron relation (CC-rate of 6-7% °C-1), according to which a warmer atmosphere is capable of holding more moisture. Nevertheless, in different locations, the scaling rate between temperature and extreme precipitation has …
Ranking world tourist destinations with a composite indicator of competitiveness: To weigh or not to weigh?
2019
Abstract This paper contributes a weighted composite indicator of competitiveness for 136 world tourist destinations. To that end, Data Envelopment Analysis and Multi-Criteria-Decision-Making techniques are used with raw indicators from the 2017 edition of the Travel & Tourism Competitiveness Report of the World Economic Forum (WEF). An outstanding feature of our approach is that weights are endogenously generated. Furthermore, the role played by several variables in tourism competitiveness is assessed using truncated regression and bootstrapping. The ranking of world tourist destinations produced by our weighted composite indicator of competitiveness is, however, fairly similar to that der…
Naturally constrained reduced form and stuctural parameters estimation
1988
To characterize such a situation, we introduce the concept of a "natural constraint", which is presented and discussed is section 1 of the present paper. Section 2 is concerned with the efficient estimation of the naturally constrained reduced form. From it, we derive efficient estimators of the structural parameters (by indirect GLS) and propose a simple test of the a priori restrictions. In section 3 we discuss estimation by 2SLS. In addition to the resultsobtained by Turkington and Pesaran, we develop a 2SLS-GLS estimator and assess its asymptotic properties. Several full information estimatorsof the 3SLS type are presented and compared in section 4 and some efficiency aspects of the ins…
Forecasting Passenger Traffic for a Regional Airport
2019
Abstract The purpose of the present research is estimating the potential traffic for SIA (Sibiu International Airport, SBZ) for the year 2017. Predicting as accurate as possible the passenger traffic for a certain airport is an aspect of major importance for both the airport management and the airline companies. The theoretical quality of the forecasting models for air traffic of passengers is fundamental for obtaining the most accurate predictions. In this regard, a two-step process was used in developing the traffic forecasting model: (1) Identifying the proper regression model for traffic estimation based on the number of aircraft departures, and (2) Forecasting the number of aircraft de…
Climate variability, innovation and firm performance: evidence from the European agricultural sector
2021
Abstract It is generally accepted that adaptation to climate variability requires a technological advancement strategy. However, the innovation process has received little explicit consideration in this framework. We employ a panel endogenous switching regression model to explore whether and to what extent climate variability affects firm performance through the ability to induce the development of adaptation innovations in key resource-based sectors in Europe during the period 2007–2017. Our findings confirm that the knowledge generation process at the heart of climate change adaptation technologies enhances firm performance, especially for firms in the aquaculture and fishing sub-sectors …
Local heterogeneities in population growth and decline. A spatial analysis for Italian municipalities
2021
Spatially unequal demographic dynamics lead to a progressive fragility of a territory and its socio-economic system. In Italy, municipalities in demographic malaise tend to be increasingly small in size and peripheral in location, and their local spatial aggregation increased over time. A spatial approach is here proposed to investigate the dynamics across time and space of the population variations in Italian municipalities. Global and local spatial autocorrelation analysis and several models of regression were run using as study variable the average growth rates at municipality level. The spatial autocorrelation of the study variable is quite high and stable over time. The regression resu…