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Influenced from the start: anchoring bias in time trade-off valuations

PURPOSE: The de facto standard method for valuing EQ-5D health states is the time trade-off (TTO), an iterative choice procedure. The TTO requires a starting point (SP), an initial offer of time in full health which is compared to a fixed offer of time in impaired health. From the SP, the time in fu...

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Autores principales: Augestad, Liv Ariane, Stavem, Knut, Kristiansen, Ivar Sønbø, Samuelsen, Carl Haakon, Rand-Hendriksen, Kim
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer International Publishing 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980414/
https://www.ncbi.nlm.nih.gov/pubmed/27016943
http://dx.doi.org/10.1007/s11136-016-1266-x
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author Augestad, Liv Ariane
Stavem, Knut
Kristiansen, Ivar Sønbø
Samuelsen, Carl Haakon
Rand-Hendriksen, Kim
author_facet Augestad, Liv Ariane
Stavem, Knut
Kristiansen, Ivar Sønbø
Samuelsen, Carl Haakon
Rand-Hendriksen, Kim
author_sort Augestad, Liv Ariane
collection PubMed
description PURPOSE: The de facto standard method for valuing EQ-5D health states is the time trade-off (TTO), an iterative choice procedure. The TTO requires a starting point (SP), an initial offer of time in full health which is compared to a fixed offer of time in impaired health. From the SP, the time in full health is manipulated until preferential indifference. The SP is arbitrary, but may influence respondents, an effect known as anchoring bias. The aim of the study was to explore the potential anchoring effect and its magnitude in TTO experiments. METHODS: A total of 1249 respondents valued 8 EQ-5D health states in a Web study. We used the lead time TTO (LT-TTO) which allows eliciting negative and positive values with a uniform method. Respondents were randomized to 11 different SPs. Anchoring bias was assessed using OLS regression with SP as the independent variable. In a secondary experiment, we compared two different SPs in the UK EQ-5D valuation study TTO protocol. RESULTS: A 1-year increase in the SP, corresponding to an increase in TTO value of 0.1, resulted in 0.02 higher recorded LT-TTO value. SP had little impact on the relative distance and ordering of the eight health states. Results were similar to the secondary experiment. CONCLUSION: The anchoring effect may bias TTO values. In this Web-based valuation study, the observed anchoring effect was substantial. Further studies are needed to determine whether the effect is present in face-to-face experiments.
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spelling pubmed-49804142016-08-19 Influenced from the start: anchoring bias in time trade-off valuations Augestad, Liv Ariane Stavem, Knut Kristiansen, Ivar Sønbø Samuelsen, Carl Haakon Rand-Hendriksen, Kim Qual Life Res Article PURPOSE: The de facto standard method for valuing EQ-5D health states is the time trade-off (TTO), an iterative choice procedure. The TTO requires a starting point (SP), an initial offer of time in full health which is compared to a fixed offer of time in impaired health. From the SP, the time in full health is manipulated until preferential indifference. The SP is arbitrary, but may influence respondents, an effect known as anchoring bias. The aim of the study was to explore the potential anchoring effect and its magnitude in TTO experiments. METHODS: A total of 1249 respondents valued 8 EQ-5D health states in a Web study. We used the lead time TTO (LT-TTO) which allows eliciting negative and positive values with a uniform method. Respondents were randomized to 11 different SPs. Anchoring bias was assessed using OLS regression with SP as the independent variable. In a secondary experiment, we compared two different SPs in the UK EQ-5D valuation study TTO protocol. RESULTS: A 1-year increase in the SP, corresponding to an increase in TTO value of 0.1, resulted in 0.02 higher recorded LT-TTO value. SP had little impact on the relative distance and ordering of the eight health states. Results were similar to the secondary experiment. CONCLUSION: The anchoring effect may bias TTO values. In this Web-based valuation study, the observed anchoring effect was substantial. Further studies are needed to determine whether the effect is present in face-to-face experiments. Springer International Publishing 2016-03-26 2016 /pmc/articles/PMC4980414/ /pubmed/27016943 http://dx.doi.org/10.1007/s11136-016-1266-x Text en © The Author(s) 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Article
Augestad, Liv Ariane
Stavem, Knut
Kristiansen, Ivar Sønbø
Samuelsen, Carl Haakon
Rand-Hendriksen, Kim
Influenced from the start: anchoring bias in time trade-off valuations
title Influenced from the start: anchoring bias in time trade-off valuations
title_full Influenced from the start: anchoring bias in time trade-off valuations
title_fullStr Influenced from the start: anchoring bias in time trade-off valuations
title_full_unstemmed Influenced from the start: anchoring bias in time trade-off valuations
title_short Influenced from the start: anchoring bias in time trade-off valuations
title_sort influenced from the start: anchoring bias in time trade-off valuations
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980414/
https://www.ncbi.nlm.nih.gov/pubmed/27016943
http://dx.doi.org/10.1007/s11136-016-1266-x
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