Modelling Noise and Imprecision in Individual Decisions

When individuals take part in decision experiments, their answers are typically subject to some degree of noise / error / imprecision. There are different ways of modelling this stochastic element in the data, and the interpretation of the data can be altered radically, depending on the assumptions made about the stochastic specification. This paper presents the results of an experiment which gathered data of a kind that has until now been in short supply. These data strongly suggest that the 'usual' (Fechnerian) assumptions about errors are inappropriate for individual decision experiments. Moreover, they provide striking evidence that core preferences display systematic departures from transitivity which cannot be attributed to any 'error' story.Error Imprecision Preferences Transitivity

Improving scope sensitivity in contingent valuation: joint and separate evaluation of health states

We present data of a contingent valuation survey, testing the effect of evaluation mode on the monetary valuation of preventing road accidents. Half of the interviewees was asked to state their willingness to pay (WTP) to reduce the risk of having only 1 type of injury (separate evaluation, SE), and the other half of the sample was asked to state their WTP for 4 types of injuries evaluated simultaneously (joint evaluation, JE). In the SE group, we observed lack of sensitivity to scope while in the JE group WTP increased with the severity of the injury prevented. However, WTP values in this group were subject to context effects. Our results suggest that the traditional explanation of the disparity between SE and JE, namely, the so-called “evaluability,” does not apply here. The paper presents new explanations based on the role of preference imprecision

El Valor Monetario de la Vida Estadística en España a través de las Preferencias Declaradas

En este trabajo estimamos el Valor Monetario de una Vida Estadística en España a partir de preferencias declaradas por la población general. El contexto de valoración elegido es el de los accidentes de tráfico. La metodología empleada es la Valoración Contingente. En la encuesta realizada se intentaron comunicar correctamente los riesgos mediante el recurso a ayudas visuales. Los valores obtenidos (no inferiores a 2,7 millones de euros) son similares a otras estimaciones efectuadas en Europa, si bien un aspecto de la consistencia de estos resultados (cuasi-proporcionalidad) sólo se verifica parcialmente. Investigaciones futuras deberán emplear estrategias alternativas a la aquí utilizada con la finalidad de intentar incrementar la consistencia de los valores obtenidos. El procedimiento “encadenado” ideado por Carthy et al. (1999) puede ser un instrumento adecuado para ese objetivo.Valor de la vida, preferencias declaradas, accidentes de tráfico, valoración contingente, comunicación de riesgos

We can’t hang out anymore: an analysis of self-other asymmetries and anti-COVID vaccination confidence in Guatemala

I conduct a survey indagating on risk perception and anti-COVID protection measures to 438 Guatemalan citizens of a high range of ages (from less than 18 to more than 60 years old) and middle to upper socio-economic level. I utilized the lottery framework developed by Holt and Laury to elicit behavior at the face of risk in two domains, financial and health. Both the survey and the risk assessments were subject to a self-other framing, in which respondents were asked to answer either on behalf of themselves or of another. Results show that Guatemalans are more risk-taking in the financial domain when deciding for themselves than for another, but both groups reported almost identical risk attitudes in the health domain. The results report a great dissociation between prosocial behavior to stop the COVID-19 spread, were people rank themselves better than others. Data also shows than being vaccinated does not increase economically active behavior, and this paper explains this in relation with the self-other dissociation found

Exploring the relative value of end of life QALYs: are the comparators important?

In the UK, life extending, end-of-life (EoL) treatments are an exception to standard cost-per-quality-adjusted life year (QALY) thresholds. This implies that greater value is placed on gaining these QALYs, than QALYs gained by the majority of other patient groups treated for anything else in the health system, even for other EoL contexts (such as quality of life (QoL) improvements alone). This paper reports a Person Trade-Off (PTO) study to test whether studies that find societal support for prioritising EoL life extensions can be explained by the severity, in terms of prospective QALYs loss, of the non-terminal comparator scenarios. Eight health scenarios were designed depicting i) QoL improvements for non-EoL temporary (T-QoL) and chronic (C-QoL) health problems and ii) QoL improvements and life extensions (LEs) for EoL health problems. Preferences were elicited from a quota sample of 901 Scottish respondents in 2016 using PTO techniques via Computer Assisted Personal Interview (CAPI). Our results indicate that there is little evidence to suggest that the severity of non-EoL comparator scenarios influence preferences for EoL treatments. Respondents do not appear to have a preference for EoL over non-EoL health gains; instead there is some indication that non-EoL health gains are preferred, particularly when compared to EoL-LE health gains. Comparing between QoL and life extending EoL scenarios, our results suggest QoL improvements are preferred to life extensions. Overall, results challenge current UK EoL policy which gives additional weight to EoL health gains, particularly EoL life extensions in the case of the National Institute for Health and Care Excellence (NICE)

La valoración monetaria de los costes humanos de la siniestralidad vial en España

ResumenLos análisis coste-beneficio en el ámbito de la seguridad vial han de computar la totalidad de los costes, y dentro de ellos ocupan un lugar clave los costes humanos. En esta nota se da cuenta de dos estudios promovidos por la Dirección General de Tráfico orientados a la obtención de valores oficiales para España de los costes asociados a las víctimas mortales y no mortales de los accidentes de tráfico. Mediante la combinación del enfoque de la valoración contingente con la técnica de la lotería estándar (modificada), y con muestras amplias (n1=2020, n2=2000) representativas de la población española, se estimó en 1,4 millones de euros el valor monetario de prevenir un fallecido por accidente de tráfico. Para las lesiones graves y leves, los valores estimados fueron de 219.000 y 6100 euros, respectivamente. Las cifras obtenidas tienen un orden de magnitud similar al de los países de nuestro entorno.AbstractCost-benefit analyses in the field of road safety compute human costs as a key component of total costs. The present article presents two studies promoted by the Directorate-General for Traffic aimed at obtaining official values for the costs associated with fatal and non-fatal traffic injuries in Spain. We combined the contingent valuation approach and the (modified) standard gamble technique in two surveys administered to large representative samples (n1=2,020, n2=2,000) of the Spanish population. The monetary value of preventing a fatality was estimated to be 1.4 million euros. Values of 219,000 and 6,100 euros were obtained for minor and severe non-fatal injuries, respectively. These figures are comparable to those observed in neighboring countries

Exploring the relative value of end of life QALYs: are the comparators important?

In the UK, life extending, end-of-life (EoL) treatments are an exception to standard cost-per-quality-adjusted life year (QALY) thresholds. This implies that greater value is placed on gaining these QALYs, than QALYs gained by the majority of other patient groups treated for anything else in the health system, even for other EoL contexts (such as quality of life (QoL) improvements alone). This paper reports a Person Trade-Off (PTO) study to test whether studies that find societal support for prioritising EoL life extensions can be explained by the severity, in terms of prospective QALYs loss, of the non-terminal comparator scenarios. Eight health scenarios were designed depicting i) QoL improvements for non-EoL temporary (T-QoL) and chronic (C-QoL) health problems and ii) QoL improvements and life extensions (LEs) for EoL health problems. Preferences were elicited from a quota sample of 901 Scottish respondents in 2016 using PTO techniques via Computer Assisted Personal Interview (CAPI). Our results indicate that there is little evidence to suggest that the severity of non-EoL comparator scenarios influence preferences for EoL treatments. Respondents do not appear to have a preference for EoL over non-EoL health gains; instead there is some indication that non-EoL health gains are preferred, particularly when compared to EoL-LE health gains. Comparing between QoL and life extending EoL scenarios, our results suggest QoL improvements are preferred to life extensions. Overall, results challenge current UK EoL policy which gives additional weight to EoL health gains, particularly EoL life extensions in the case of the National Institute for Health and Care Excellence (NICE)

EQ-5D-5L valuation project for the Spanish population: a descriptive overview and preliminary results

The latest EQ-5D instrument, EQ-5D-5L, needs new country-specific valuation studies to obtain a value set adapted to the characteristics of the updated instrument. Eight countries from Europe, North and South America and Asia have participated on pilot exercises to develop a final protocol which will be commonly used to perform the valuation studies in each country. Spain is the first country where this protocol has been introduced as part of the Valuation Project for the Spanish Population. This discussion paper reports a descriptive overview of EQ-5D-5L valuation results in the Spanish population and its preliminary results.The survey has a two-stage sample plan. The first stage concentrates on the selection of Spanish regions. The 50 Spanish regions were ordered by population size, and the first 20 regions covering 80% of the total Spanish population were selected. In the second stage, a simple random sampling strategy on each of the selected regions was conducted. The sample size on each region was calculated multiplying the total sample size (1,000) by the percentage of the population on the region respect the total population of the select 20 regions. Data will be collected between 21st May and 15th June 2012 using the final agreed protocol by the EuroQol group. Primary data collection will be conducted by a specialist survey company with a second company conducting a strict quality control process to ensure interviews and data collection of highest quality. The final survey has three blocks of questions. The first block includes patient characteristics (age, gender, socioeconomic status and so on), and a respondent valuation of own health using the EQ-5D-5L. The second block contains 10 composite time trade-offs (TTO) questions, for states better than death classic TTO is used and the “Lead Time” TTO is used for those health states considered worse than death. In this case the lead time (period in full health) is 10 years and the time in the disease is another 10 years to be comparable with the classical TTO were there are 10 years in full health and 10 years in the disease. The last block contains 7 discrete choice experiments questions, where the participant has to choose between two states. Finally some questions about the difficulties of the survey are also included. Descriptive statistics of the final sample are reported. A detailed overview of summary statistics for the health state valuations is included. Different models were explored; hybrid TTO and DC model and DC conditional logistic rescaled with TTO values were used and compared

Handling data quality issues to estimate the Spanish EQ-5D-5L value set using a hybrid interval regression approach

Background The Spanish five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) valuation study was the first to use the EuroQol Valuation Technology protocol, including composite time trade-off (C-TTO) and discrete choice experiments (DCE). In this study, its investigators noticed that some interviewers did not fully explain the C-TTO task to respondents. Evidence from a follow-up study in 2014 confirmed that when interviewers followed the protocol, the distribution of C-TTO responses widened. Objectives To handle the data quality issues in the C-TTO responses by estimating a hybrid interval regression model to produce a Spanish EQ-5D-5L value set. Methods Four different models were tested. Model 0 integrated C-TTO and DCE responses in a hybrid model and models 1 to 3 altered the interpretation of the C-TTO responses: model 1 allowed for censoring of the C-TTO responses, whereas model 2 incorporated interval responses and model 3 included the interviewer-specific protocol violations. For external validation, the predictions of the four models were compared with those of the follow-up study using the Lin’s concordance correlation coefficient. Results This stepwise approach to modeling C-TTO and DCE responses improved the concordance between the valuation and follow-up studies (concordance correlation coefficient: 0.948 [model 0], 0.958 [model 1], 0.952 [model 2], and 0.989 [model 3]). We recommend the estimates from model 3, because its hybrid interval regression model addresses the data quality issues found in the valuation study. Conclusions Protocol violations may occur in any valuation study; handling them in the analysis can improve external validity. The resulting EQ-5D-5L value set (model 3) can be applied to inform Spanish health technology assessments

¿Qué es una intervención sanitaria eficiente en España en 2020?

Hace más de 15 años que en Gaceta Sanitaria se publicó el artículo titulado «¿Qué es una tecnología sanitaria eficiente en España?». El creciente interés por fijar el precio de las nuevas tecnologías en función del valor que estas proporcionan a los sistemas de salud y la experiencia acumulada por los países de nuestro entorno hacen oportuno revisar qué es una intervención sanitaria eficiente en España en el año 2020. El análisis de coste-efectividad sigue siendo el método de referencia para maximizar los resultados en salud de la sociedad con los recursos disponibles. La interpretación de sus resultados requiere establecer unos valores de referencia que sirvan de guía sobre lo que constituye un valor razonable para el sistema sanitario. Los umbrales de eficiencia deben ser flexibles y dinámicos, y actualizarse periódicamente. Su aplicación debe estar basada en la gradualidad y la transparencia, considerando, además, otros factores que reflejen las preferencias sociales. Aunque la fijación de los umbrales corresponde a los decisores políticos, en España puede ser razonable utilizar unos valores de referencia como punto de partida que podrían estar comprendidos entre los 25.000 y los 60.000 euros por año de vida ajustado por calidad. No obstante, en la actualidad, más que la determinación de las cifras exactas de dicho umbral, la cuestión clave es si el Sistema Nacional de Salud está preparado y dispuesto a implantar un modelo de pago basado en el valor, que contribuya a lograr la gradualidad en las decisiones de financiación y, sobre todo, a mejorar la previsibilidad, la consistencia y la transparencia del proceso.Fifteen years ago, Gaceta Sanitaria published the article entitled “What is an efficient health technology in Spain?” The growing interest in setting the price of new technologies based on the value they provide to health systems and the experience accumulated by the countries in our environment make it opportune to review what constitutes an efficient health intervention in Spain in 2020. Cost-effectiveness analysis continues to be the reference method to maximize social health outcomes with the available resources. The interpretation of its results requires establishing reference values that serve as a guide on what constitutes a reasonable value for the health care system. Efficiency thresholds must be flexible and dynamic, and they need to be updated periodically. Its application should be based on and transparency, and consider other factors that reflect social preferences. Although setting thresholds is down to political decision-makers, in Spain it could be reasonable to use thresholds of 25,000 and 60,000 Euros per QALY. However, currently, in addition to determining exactfigures for the threshold,the key question is whether the Spanish National Health System is able and willing to implement a payment model based on value, towards achieving gradual financing decisions and, above all, to improve the predictability, consistency and transparency of the process