A Sensitivity analysis of poverty definitions

We conduct a sensitivity analysis of several estimators related to household income, to explore how some details of the definitions of the variables concerned influence the values of the common estimates, such as the mean, median and (poverty) rates. The purpose of this study is to highlight that some of the operational definitions entail an element of arbitrariness which leaves an undesirable stamp on the inferences made. The analyses use both a cross-sectional and a longitudinal (panel) component of the EU-SILC database.

A correlation sensitivity analysis of non-life underwriting risk in solvency capital requirement estimation

This paper analyses the impact of using different correlation assumptions between lines of business when estimating the risk-based capital reserve, the Solvency Capital Requirement (SCR), under Solvency II regulations. A case study is presented and the SCR is calculated according to the Standard Model approach. Alternatively, the requirement is then calculated using an Internal Model based on a Monte Carlo simulation of the net underwriting result at a one-year horizon, with copulas being used to model the dependence between lines of business. To address the impact of these model assumptions on the SCR we conduct a sensitivity analysis. We examine changes in the correlation matrix between lines of business and address the choice of copulas. Drawing on aggregate historical data from the Spanish non-life insurance market between 2000 and 2009, we conclude that modifications of the correlation and dependence assumptions have a significant impact on SCR estimation.

Analysis of sensitivity with respect to a compositional parameter : A comment on 'Local sensitivity analysis for compositional data with application to soil texture in hydrologic modelling' by L. Loosvelt and co-authors

A comment about the article “Local sensitivity analysis for compositional data with application to soil texture in hydrologic modelling” writen by L. Loosvelt and co-authors. The present comment is centered in three specific points. The first one is related to the fact that the authors avoid the use of ilr-coordinates. The second one refers to some generalization of sensitivity analysis when input parameters are compositional. The third tries to show that the role of the Dirichlet distribution in the sensitivity analysis is irrelevant

A correlation sensitivity analysis of non-life underwriting risk in solvency capital requirement estimation

This paper analyses the impact of using different correlation assumptions between lines of business when estimating the risk-based capital reserve, the Solvency Capital Requirement -SCR-, under Solvency II regulations. A case study is presented and the SCR is calculated according to the Standard Model approach. Alternatively, the requirement is then calculated using an Internal Model based on a Monte Carlo simulation of the net underwriting result at a one-year horizon, with copulas being used to model the dependence between lines of business. To address the impact of these model assumptions on the SCR we conduct a sensitivity analysis. We examine changes in the correlation matrix between lines of business and address the choice of copulas. Drawing on aggregate historical data from the Spanish non-life insurance market between 2000 and 2009, we conclude that modifications of the correlation and dependence assumptions have a significant impact on SCR estimation.

Has concentration evolved similarly in manufacturing and services? A sensitivity analysis

Our first objective is to compare the degree of concentration in manufacturing and services, with special emphasis on its evolution in these two sectors, using a sensitivity analysis for different concentration indices and different geographic units of analysis: municipalities and local labour systems of Catalonia in 1991 and 2001. Most concentration measures fail to consider the space in which a particular municipality is located. Our second objective is to overcome this problem by applying two different techniques: by using a clustering measure, and by analysing whether the location quotients computed for each municipality and sector present some kind of spatial autocorrelation process. We take special account of the differences in patterns of concentration according to the technological level of the sectors.

Analysis of leakage properties and guiding conditions of rib antiresonant reflecting optical waveguides

Power leakage properties and guiding conditions of rib antiresonant reflecting optical waveguides (rib-ARROW) have been theoretically and experimentally studied as a function of wavelength and polarization of the light for different geometrical and optical parameters that characterize the rib-ARROW structure. Obtained results show that rib-ARROWs can only be fabricated with low losses in a wavelength range when determined rib configurations are adopted. Furthermore, these waveguides exhibit a polarization sensitivity that largely depends on the core-substrate refractive index difference. Together with the experimental results, theoretical calculations from different modeling methods are also presented and discussed.

Cost-effectiveness analysis of cardiac resynchronization therapy in patients with NYHA I and NYHA II heart failure in Spain

Objectives: The aim of the study was to combine clinical results from the European Cohort of the REVERSE study and costs associated with the addition of cardiac resynchronization therapy (CRT) to optimal medical therapy (OMT) in patients with mild symptomatic (NYHA I-II) or asymptomatic left ventricular dysfunction and markers of cardiac dyssynchrony in Spain. Methods: A Markov model was developed with CRT + OMT (CRT-ON) versus OMT only (CRT-OFF) based on a retrospective cost-effectiveness analysis. Raw data was derived from literature and expert opinion, reflecting clinical and economic consequences of patient"s management in Spain. Time horizon was 10 years. Both costs (euro 2010) and effects were discounted at 3 percent per annum. Results: CRT-ON showed higher total costs than CRT-OFF; however, CRT reduced the length of hospitalization in ICU by 94 percent (0.006 versus 0.091 days) and general ward in by 34 percent (0.705 versus 1.076 days). Surviving CRT-ON patients (88.2 percent versus 77.5 percent) remained in better functional class longer, and they achieved an improvement of 0.9 life years (LYGs) and 0.77 years quality-adjusted life years (QALYs). CRT-ON proved to be cost-effective after 6 years, except for the 7th year due to battery depletion. At 10 years, the results were 18,431 per LYG and 21,500 per QALY gained. Probabilistic sensitivity analysis showed CRT-ON was cost-effective in 75.4 percent of the cases at 10 years. Conclusions: The use of CRT added to OMT represents an efficient use of resources in patients suffering from heart failure in NYHA functional classes I and II.

Modelling the cardiovascular system for automatic interpretation of the blood pressure curve

A four compartment model of the cardiovascular system is developed. To allow for easy interpretation and to minimise the number of parameters, an effort was made to keep the model as simple as possible. A sensitivity analysis is first carried out to determine which are the most important model parameters to characterise the blood pressure signal. A four stage process is then described which accurately determines all parameter values. This process is applied to data from three patients and good agreement is shown in all cases.

Using a Parameterization of a Radiative Transfer Model to Build High-Resolution Maps of Typical Clear-Sky UV Index in Catalonia, Spain

To perform a climatic analysis of the annual UV index (UVI) variations in Catalonia, Spain (northeast of the Iberian Peninsula), a new simple parameterization scheme is presented based on a multilayer radiative transfer model. The parameterization performs fast UVI calculations for a wide range of cloudless and snow-free situations and can be applied anywhere. The following parameters are considered: solar zenith angle, total ozone column, altitude, aerosol optical depth, and single-scattering albedo. A sensitivity analysis is presented to justify this choice with special attention to aerosol information. Comparisons with the base model show good agreement, most of all for the most common cases, giving an absolute error within 0.2 in the UVI for a wide range of cases considered. Two tests are done to show the performance of the parameterization against UVI measurements. One uses data from a high-quality spectroradiometer from Lauder, New Zealand [45.04°S, 169.684°E, 370 m above mean sea level (MSL)], where there is a low presence of aerosols. The other uses data from a Robertson–Berger-type meter from Girona, Spain (41.97°N, 2.82°E, 100 m MSL), where there is more aerosol load and where it has been possible to study the effect of aerosol information on the model versus measurement comparison. The parameterization is applied to a climatic analysis of the annual UVI variation in Catalonia, showing the contributions of solar zenith angle, ozone, and aerosols. High-resolution seasonal maps of typical UV index values in Catalonia are presented

International business cycles, financial markets and household production

This paper investigates the properties of an international real business cycle model with household production. We show that a model with disturbances to both market and household technologies reproduces the main regularities of the data and improves existing models in matching international consumption, investment and output correlations without irrealistic assumptions on the structure of international financial markets. Sensitivity analysis shows the robustness of the results to alternative specifications of the stochastic processes for the disturbances and to variations of unmeasured parameters within a reasonable range.

Deciding the sale of a life policy in the viatical market: Implications on individual welfare

[cat] En aquest article, es presenta un model econòmic que permet determinar la venda o no d'una pòlissa de vida (total o en part) per part d'un assegurat malalt terminal en el mercat dels viatical settlements. Aquest mercat va aparèixer a finals de la dècada dels 80 a conseqüència de l'epidèmia de la SIDA. Actualment, representa una part del mercat dels life settlements. Les pòlisses que es comercialitzen en el mercat dels viaticals són aquelles on l'assegurat és malalt terminal amb una esperança de vida de dos anys o menys. El model és discret i considera només dos períodes (anys), ja que aquesta és la vida residual màxima que contempla el mercat. L'agent posseix una riquesa inicial que ha de repartir entre consum i herència. S'introdueix en primer lloc la funció d'utilitat esperada del decisor i, utilitzant programació dinàmica, es dedueix l'estratègia que reporta una utilitat més gran (no vendre/vendre (en part) la pòlissa en el moment zero/vendre (en part) la pòlissa en el moment ú). L'òptim depèn del preu de la pòlissa venuda i de paràmetres personals de l'individu. Es troba una expressió analítica per l'estratègia òptima i es realitza un anàlisi de sensibilitat.

Deciding the sale of a life policy in the viatical market: Implications on individual welfare

[cat] En aquest article, es presenta un model econòmic que permet determinar la venda o no d'una pòlissa de vida (total o en part) per part d'un assegurat malalt terminal en el mercat dels viatical settlements. Aquest mercat va aparèixer a finals de la dècada dels 80 a conseqüència de l'epidèmia de la SIDA. Actualment, representa una part del mercat dels life settlements. Les pòlisses que es comercialitzen en el mercat dels viaticals són aquelles on l'assegurat és malalt terminal amb una esperança de vida de dos anys o menys. El model és discret i considera només dos períodes (anys), ja que aquesta és la vida residual màxima que contempla el mercat. L'agent posseix una riquesa inicial que ha de repartir entre consum i herència. S'introdueix en primer lloc la funció d'utilitat esperada del decisor i, utilitzant programació dinàmica, es dedueix l'estratègia que reporta una utilitat més gran (no vendre/vendre (en part) la pòlissa en el moment zero/vendre (en part) la pòlissa en el moment ú). L'òptim depèn del preu de la pòlissa venuda i de paràmetres personals de l'individu. Es troba una expressió analítica per l'estratègia òptima i es realitza un anàlisi de sensibilitat.

Psychometric evaluation of the IWQOL-Lite (Spanish version) when applied to a sample of obese patients awaiting bariatric surgery

Background Obesity may have an impact on key aspects of health-related quality of life (HRQOL). In this context, the Impact of Weight Quality of Life (IWQOL) questionnaire was the first scale designed to assess HRQOL. The aim of the present study was twofold: to assess HRQOL in a sample of Spanish patients awaiting bariatric surgery and to determine the psychometric properties of the IWQOL-Lite and its sensitivity to detect differences in HRQOL across groups. Methods Participants were 109 obese adult patients (BMI¿ 35 kg/m2) from Barcelona, to whom the following measurement instruments were applied: IWQOL-Lite, Depression Anxiety Stress Scales, Brief Symptom Inventory, and self-perception items. Results Descriptive data regarding the IWQOL-Lite scores obtained by these patients are reported. Principal components analysis revealed a five-factor model accounting for 72.05% of the total variance, with factor loadings being adequate for all items. Corrected itemtotal correlations were acceptable for all items. Cronbach"s alpha coefficients were excellent both for the subscales (0.880.93) and the total scale (0.95). The relationship between the IWQOLLite and other variables supports the construct validity of the scale. Finally, sensitivity analysis revealed large effect sizes when comparing scores obtained by extreme BMI groups. Conclusions This is the first study to report the application of the IWQOL-Lite to a sample of Spanish patients awaiting bariatric surgery and to confirm that the Spanish version of the instrument has adequate psychometric properties.

Economic evaluation of the levonorgestrel-releasing intrauterine system for the treatment of dysfunctional uterine bleeding in Spain

To compare the cost and effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) versus combined oral contraception (COC) and progestogens (PROG) in first-line treatment of dysfunctional uterine bleeding (DUB) in Spain. STUDY DESIGN: A cost-effectiveness and cost-utility analysis of LNG-IUS, COC and PROG was carried out using a Markov model based on clinical data from the literature and expert opinion. The population studied were women with a previous diagnosis of idiopathic heavy menstrual bleeding. The analysis was performed from the National Health System perspective, discounting both costs and future effects at 3%. In addition, a sensitivity analysis (univariate and probabilistic) was conducted. RESULTS: The results show that the greater efficacy of LNG-IUS translates into a gain of 1.92 and 3.89 symptom-free months (SFM) after six months of treatment versus COC and PROG, respectively (which represents an increase of 33% and 60% of symptom-free time). Regarding costs, LNG-IUS produces savings of 174.2-309.95 and 230.54-577.61 versus COC and PROG, respectively, after 6 months-5 years. Apart from cost savings and gains in SFM, quality-adjusted life months (QALM) are also favourable to LNG-IUS in all scenarios, with a range of gains between 1 and 2 QALM compared to COC and PROG. CONCLUSIONS: The results indicate that first-line use of the LNG-IUS is the dominant therapeutic option (less costly and more effective) in comparison with first-line use of COC or PROG for the treatment of DUB in Spain. LNG-IUS as first line is also the option that provides greatest health-related quality of life to patients.

Economic evaluation of the levonorgestrel-releasing intrauterine system for the treatment of dysfunctional uterine bleeding in Spain

To compare the cost and effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) versus combined oral contraception (COC) and progestogens (PROG) in first-line treatment of dysfunctional uterine bleeding (DUB) in Spain. STUDY DESIGN: A cost-effectiveness and cost-utility analysis of LNG-IUS, COC and PROG was carried out using a Markov model based on clinical data from the literature and expert opinion. The population studied were women with a previous diagnosis of idiopathic heavy menstrual bleeding. The analysis was performed from the National Health System perspective, discounting both costs and future effects at 3%. In addition, a sensitivity analysis (univariate and probabilistic) was conducted. RESULTS: The results show that the greater efficacy of LNG-IUS translates into a gain of 1.92 and 3.89 symptom-free months (SFM) after six months of treatment versus COC and PROG, respectively (which represents an increase of 33% and 60% of symptom-free time). Regarding costs, LNG-IUS produces savings of 174.2-309.95 and 230.54-577.61 versus COC and PROG, respectively, after 6 months-5 years. Apart from cost savings and gains in SFM, quality-adjusted life months (QALM) are also favourable to LNG-IUS in all scenarios, with a range of gains between 1 and 2 QALM compared to COC and PROG. CONCLUSIONS: The results indicate that first-line use of the LNG-IUS is the dominant therapeutic option (less costly and more effective) in comparison with first-line use of COC or PROG for the treatment of DUB in Spain. LNG-IUS as first line is also the option that provides greatest health-related quality of life to patients.