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- Modelling health state preference data using fixed and random effects modelsPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Pereira, Luis NobreThe use of preference-based measures of health in the measurement of Health Related Quality of Life has become widely used in health economics. Hence, the development of preference-based measures of health has been a major concern for researchers throughout the world. This study aims to model health state preference data using a new preference-based measure of health (the SF- 6D) and to suggest alternative models for predicting health state utilities using fixed and random effects models. It also seeks to investigate the problems found in the SF-6D and to suggest eventual changes to it.
- Comparing the performance of the SF-6D and EQ-5D across diseasesPublication . Ferreira, L.; Ferreira, P.; Pereira, L.
- Exploring the consistency of the SF-6DPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Pereira, Luis; Rowen, Donna; Brazier, John E.Objective: The six dimensional health state short form (SF-6D) was designed to be derived from the short-form 36 health survey (SF-36). The purpose of this research was to compare the SF-6D index values generated from the SF 36 (SF-6D(SF-36)) with those obtained from the SF-6D administered as an independent instrument (SF-6D(Ind)). The goal was to assess the consistency of respondents answers to these two methods of deriving the SF-6D. Methods: Data were obtained from a sample of the Portuguese population (n = 414). Agreement between the instruments was assessed on the basis of a descriptive system and their indexes. The analysis of the descriptive system was performed by using a global consistency index and an identically classified index. Agreement was also explored by using correlation coefficients. Parametric tests were used to identify differences between the indexes. Regression models were estimated to understand the relationship between them. Results: The SF-6D(Ind) generates higher values than does the SF-6D(SF-36), There were significant differences between the indexes across sociodemographic groups. There was a significant ceiling effect in the SF-6D(Ind) a but not in the SF-6D(SF-36). The correlation between the indexes was high but less than what was anticipated. The global consistency index identified the dimensions with larger differences. Considerable differences were found in two dimensions, possibly as a result of different item contexts. Further research is needed to fully understand the role of the different layouts and the length of the questionnaires in the respondents' answers. Conclusions: The results show that as the SF-6D was designed to derive utilities from the SF-36 it should be used in this way and not as an independent instrument.
- A tourism research agenda for PortugalPublication . Silva, João Albino; Rodrigues, Paulo M. M.; Mendes, Júlio; Pereira, Luis NobreThe need to direct research towards the tourism industry is related to the increasingly competitive environment it fi nds itself in, especially in terms of services rendered, having grown more complex in the features and critique that comprise the tourist experience, and as economic and social agents become more selective regarding both demand and supply. Possessing information and the proper understanding of the real needs of information users and those responsible for public and private decision-making processes at the action and intervention levels becomes a fundamental issue for sustainable tourism growth and its statement for international competitiveness. This paper proposes a tourism research agenda for Portugal in order to guide future developments towards the industry’s needs.
- The economic impact of recreational trails: a systematic literature reviewPublication . Lukoseviciute, Goda; Pereira, LN; Panagopoulos, ThomasRecreational trails are a type of nature-based tourism providing various activities such as hiking, biking, rafting or horseback riding. Increasing investment in infrastructure and touristic services development has resulted in higher visitor expenditure and thus contributed to economic development. This study aims to review the current economic impact assessment studies on recreational trail tourism and to extract the main economic impact determinants. A systematic literature review analysis was applied in a quantitative approach about economic models, study cases of nature-based tourism, comparison of economic impacts. A qualitative analysis was then applied with an inductive approach to compare the economic impacts of nature-based tourism forms and identify the main determinants of economic impact. This study suggests that I-O is the most suitable theoretical approach to study the economic impact of long-distance trails, while the Keynesian multiplier approach and Ad hoc model are the most suitable approaches to study the economic impact of short-distance trails.
- An introduction to helpful forecasting methods for hotel revenue managementPublication . Pereira, LuisRevenue management is a key tool for hotel managers' decision-making process. Cutting-edge revenue management systems have been developed to support managers' decisions and all have as an essential component an accurate forecasting module. This paper aims to introduce new time series forecasting models to be considered as a tool for forecasting daily hotel occupancies. These models were developed in a state space modelling framework which is capable of tackling seasonal complexities such as multiple seasonal periods and non-integer seasonality. An empirical study was carried out to illustrate how a practitioner may apply and compare the performance of different models when forecasting a hotel's daily occupancy. Results showed that the trigonometric model based on the new modelling framework generally outperformed the majority of the other models. These findings are potentially useful to the entire revenue management community facing the challenge of accurately forecasting a hotel's daily demand. (C) 2016 Elsevier Ltd. All rights reserved.
- A hybrid modelling approach for eliciting health state preferences: the Portuguese EQ-5D-5L value setPublication . Ferreira, Pedro L.; Antunes, Patricia; Ferreira, Lara; Pereira, LN; Ramos-Goni, Juan M.Background The EQ-5D is a generic preference-based quality of life measure considered useful for supporting clinical and policy decisions by providing utility values that can easily be converted into quality-adjusted life years to be integrated in cost-utility economic evaluations. Although the three-level classification system of the EuroQol questionnaire (EQ-5D-3L) is still the most popular preference-based instrument used worldwide, several studies reported a ceiling effect on this version, especially in healthy and/or young individuals. In 2009, the EuroQol Group introduced a five-level EQ-5D, which expands the descriptive system from three to five levels within the same five dimensions. For this version to be used in health economic evaluation, societal values need to be assigned to the 3125 health states generated by this instrument. Objectives The aims of this study were to elicit the EQ-5D-5L health state preferences from the general Portuguese population and to derive the Portuguese value set for the EQ-5D-5L. Methods A representative sample of the Portuguese general population aged above 18 years was stratified by age and gender (n = 1451). Between October 2015 and July 2016, 28 interviewers carried out a series of 1-h-long computer-assisted personal interviews following the EuroQol Valuation Technology protocol. Each interview included the valuation of ten health states using the composite time trade-off (cTTO) and seven pairs of discrete choice experiments (DCEs). A standardized tool for quality control was used to assess the quality of the data as well as direct supervision and cross-examination of 10% of the global sample size. Data from both cTTO and DCE valuation tasks were modelled using a censored heteroskedastic hybrid model. Results Interviewers complied with the quality control protocol in providing high-quality valuation data. The hybrid econometric model had consistent and significant parameters. The derived societal values for the Portuguese population ranged from - 0.603 to 1. Conclusion This study provided the Portuguese value set for the EQ-5D-5L on the basis of a hybrid econometric model using cTTO and DCE data. These results represent the preferences of the Portuguese population and are recommended to inform health decision-making in Portugal.
- Small Area Estimation of the Mean Price of the Habitation Transaction in Portugal: Methodological and Practical IssuesPublication . Pereira, Luis Nobre; Coelho, Pedro S.The Portuguese National Statistical Institute intends to produce estimations for the mean price of the habitation transation.
- O sistema português de valores do SF-6DPublication . Ferreira, Pedro L.; Ferreira, Lara Noronha; Pereira, Luis NobreIntrodução: Nos últimos tempos tem-se assistido ao desenvolvimento de estudos em alguns países, de forma a obter funções de valoração relativas aos instrumentos de medição de preferências mais utilizados. Na verdade, a evidência sugere que as valorações dos estados de saúde podem diferir de país para país. O objectivo deste estudo foi a determinação de um sistema de valores subjacente ao SF-6D para Portugal. Metodologia: Uma amostra de 55 estados de saúde definidos pelo SF-6D foi valorizada por uma amostra aleatória estratificada da população em geral, utilizando o standard gamble (SG). A pesquisa foi conduzida por entrevistas pessoais, tendo os respondentes valorizado seis estados de saúde, acrescidos do pior estado de saúde definido pelo SF-6D ou da morte imediata. Estimaram-se vários modelos com o objectivo de prever as valorações dos estados de saúde. Numa primeira fase, foram estimados modelos lineares, tanto ao nível individual, como agregado, assim como modelos com efeitos fixos, com efeitos principais e de interacção e com a constante forçada à unidade. Numa segunda fase, foram ainda testados, pelo método dos mínimos quadrados generalizados, modelos com efeitos aleatórios (MEA). Foram também estimados MEA com a constante forçada à unidade pelas equações de estimação generalizadas (EEG). Consideraram-se especificações alternativas, como forma de tomar em consideração o enviesamento das valorações dos estados de saúde. Os modelos foram analisados em termos dos seus coeficientes, ajustamento e capacidade para prever os valores dos estados de saúde captados pelo SG. Resultados: Os MEA e os modelos EEG produziram coeficientes significativos, que se verificou serem robustos nas especificações dos modelos. A utilização de uma bateria de medidas de bondade do ajustamento levou à conclusão que o modelo EEG com efeitos principais era o melhor modelo estimado. Conclusão: Esta investigação demonstra que é possível obter sistemas de pesos para a medição da qualidade de vida relacionada com a saúde. O melhor modelo obtido parece prever adequadamente os valores dos estados de saúde da população portuguesa. No entanto, existem algumas incoerências que devem ser investigadas.
- Aplicação de sondagens indirectas no turismoPublication . Pereira, Luis Nobre; Coelho, Pedro S.Na maioria das sondagens realizadas na área do turismo não existe uma base de amostragem da população alvo. Em seu lugar, pode existir uma base de amostragem formada por unidades de amostragem de outra população, as quais estão relacionadas, de alguma forma, com as unidades estatísticas de análise que se pretendem inquirir. Esta situação provoca um problema no que concerne à dificuldade de associar uma probabilidade de inclusão a cada unidade amostral da população alvo. Uma solução para esse problema consiste em aplicar o método de sondagem indirecta e utilizar o Método de Partilha de Pesos Generalizado (MPPG) desenvolvido por Lavallée (1995, 2002), na atribuição dos pesos de estimação a cada unidade amostral da população alvo. Este artigo é dedicado à apresentação do método de sondagem indirecta e da forma de determinação dos pesos da estimação, através do MPPG, e a sua adaptação à resolução de problemas de estimação na área do turismo em ambiente aberto.