Improving the Valuation of the EQ-5D-5L by Introducing Quality Control and Integrating TTO and DCE

Background: Recently, a new version of the standard EQ-5D questionnaire called EQ-5D-5L with 5 levels on each dimension was developed. To make the EQ-5D-5L suitable for use in economic evaluations, national value sets need to be developed. A standardized valuation protocol has been suggested for that purpose, to enable comparison of values across countries. This protocol included two elicitation techniques, the ‘composite time trade-off’ (C-TTO), and ‘discrete choice experiments’ (DCE). This thesis describes experiences with first use of that standardized protocol and major evolvements happening to it since, with a focus on the following three questions: 1) What problems may be encountered in the use of the EQ-5D-5L valuation protocol to generate national value sets? 2) How can the protocol be improved? 3) How can the produced data best be modelled to develop a value set? Conclusions: The studies presented in this thesis, together with similar work accomplished elsewhere, have resulted in an evolved valuation protocol for the EQ-5D-5L instrument, paired with a quality assurance procedure and novel analytical approaches. The updated protocol has enabled teams from all over the world to successfully establish EQ-5D-5L value sets

Quality Control Process for EQ-5D-5L Valuation Studies

Background: The values of the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) are elicited using composite time trade-off and discrete choice experiments. Unfortunately, data quality issues and interviewer effects were observed in the first few EQ-5D-5L valuation studies. To prevent these issues from occurring in later studies, the EuroQol Group established a cyclic quality control (QC) process. Objectives: To describe this QC process and show its impact on data quality. Methods: A newly developed QC tool provided information about protocol compliance, interviewer effects, and mean values by health state severity. In a cyclic process, this information is initially used to evaluate whether new interviewers meet minimal quality requirements and later to provide feedback about how their performance may be improved. To investigate the impact of this cyclic process, we compared the quality of the data in Dutch and Spanish valuation studies that did not have this QC process with that in the follow-up studies in the same countries that used the QC process. Data quality was measured using protocol violations, variability between interviewers, the proportion of inconsistent responders, and clustering of composite time trade-off values. Results: In Spain, protocol violations were reduced from 87% in the valuation study to 5% in the follow-up study and in the Netherlands from 20% to 8%. In both countries, interviewers performed more homogeneously in the follow-up studies. The number of inconsistent respondents was reduced by 23.2% in Spain and 23.6% in the Netherlands. Values were less clustered in the follow-up studies. Conclusions: The implementation of a strict QC process in EQ-5D-5L valuation studies increases interviewer protocol compliance and promotes data quality

The Indonesian EQ-5D-5L Value Set

Background: The EQ-5D is one of the most used generic health-related quality-of-life (HRQOL) instruments worldwide. To make the EQ-5D suitable for use in economic evaluations, a societal-based value set is needed. Indonesia does not have such a value set. Objective: The aim of this study was to derive an EQ-5D-5L value set from the Indonesian general population. Methods: A representative sample aged 17 years and over was recruited from the Indonesian general population. A multi-stage stratified quota method with respect to residence, gender, age, level of education, religion and ethnicity was utilized. Two elicitation techniques, the composite time trade-off (C-TTO) and discrete choice experiments (DCE) were applied. Interviews were undertaken by trained interviewers using computer-assisted face-to-face interviews with the EuroQol Valuation Technology (EQ-VT) platform. To estimate the value set, a hybrid regression model combining C-TTO and DCE data was used. Results: A total of 1054 respondents who completed the interview formed the sample for the analysis. Their characteristics were similar to those of the Indonesian population. Most self-reported health problems were observed in the pain/discomfort dimension (39.66%) and least in the self-care dimension (1.89%). In the value set, the maximum value was 1.000 for full health (health state ‘11111’) followed by the health state ‘11112’ with value 0.921. The minimum value was −0.865 for the worst state (‘55555’). Preference values were most affected by mobility and least by pain/discomfort. Conclusions: We now have a representative EQ-5D-5L value set for Indonesia. We expect our results will promote and facilitate health economic evaluations and HRQOL research in Indonesia

Learning and satisficing: An analysis of sequence effects in health valuation

Objective To estimate the effect of sequence on response precision and response behavior in health valuation studies. Methods Time trade-off (TTO) and paired comparison responses from six health valuation studies - four US, one Spanish, and one Dutch - were examined (22,225 respondents) to test whether task sequence influences response precision (e.g., rounding), response changes, and median response times. Each study used a computer-based instrument that randomized task sequence among a national sample of adults, age 18 years or older, from the general population. Results For both TTO and paired comparisons, median response times decreased with sequence (i.e., learning), but tended to flatten after the first three tasks. Although the paired comparison evidence demonstrated that sequence had no effect on response precision, the frequency of rounded TTO responses (to either 1-year or 5-year units) increased with sequence. Conclusions Based on these results, randomizing or reducing the number of paired comparison tasks does not appear to influence response precision; however, generalizability, practicality, and precautionary consider