Juan M Ramos-Goñi1, Mark Oppe2, Bernhard Slaap2, Jan J V Busschbach3, Elly Stolk4. 1. Executive Office, EuroQol Research Foundation, Rotterdam, The Netherlands. Electronic address: jramos@euroqol.org. 2. Executive Office, EuroQol Research Foundation, Rotterdam, The Netherlands. 3. Section of Medical Psychology, Department of Psychiatry, Erasmus MC, Rotterdam, The Netherlands. 4. Executive Office, EuroQol Research Foundation, Rotterdam, The Netherlands; Institute for Health Policy and Management, Erasmus University, Rotterdam, The Netherlands.
Abstract
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.
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.
Authors: Pedro L Ferreira; Patrícia Antunes; Lara N Ferreira; Luís N Pereira; Juan M Ramos-Goñi Journal: Qual Life Res Date: 2019-06-14 Impact factor: 4.147
Authors: Richard Huan Xu; Dong Dong; Nan Luo; Eliza Lai-Yi Wong; Renchi Yang; Junshuai Liu; Huiqin Yuan; Shuyang Zhang Journal: Qual Life Res Date: 2021-11-30 Impact factor: 4.147