BACKGROUND: Conditions were studied that may invalidate health-state values derived from the visual analogue scale (VAS). METHODS: Respondents were asked to place cards with descriptions of EQ-5D health states on a 20 cm EuroQol VAS and modified versions of it, positioning them such that the distances between the states reflect their valuation for these states. Anchor-point bias was examined using the standard EuroQol VAS (n = 212) and a modified version (n = 97) with a different lower anchor. Context bias was examined in another group of respondents (n = 112) who valued three different sets of EQ-5D health states. Marker bias was studied in yet another group of respondents (n = 100) who placed the same EQ-5D states on the standard EuroQol VAS and on a modified VAS without anchors, categories, or measurement markers. RESULTS: No indication for the existence of the anchor-point and the marker bias was found. However, the VAS valuations were significantly affected by the context of the set of health states in the scaling task. CONCLUSION: Advanced methodologies should be incorporated in VAS valuation studies to deal with the context bias.
BACKGROUND: Conditions were studied that may invalidate health-state values derived from the visual analogue scale (VAS). METHODS: Respondents were asked to place cards with descriptions of EQ-5D health states on a 20 cm EuroQol VAS and modified versions of it, positioning them such that the distances between the states reflect their valuation for these states. Anchor-point bias was examined using the standard EuroQol VAS (n = 212) and a modified version (n = 97) with a different lower anchor. Context bias was examined in another group of respondents (n = 112) who valued three different sets of EQ-5D health states. Marker bias was studied in yet another group of respondents (n = 100) who placed the same EQ-5D states on the standard EuroQol VAS and on a modified VAS without anchors, categories, or measurement markers. RESULTS: No indication for the existence of the anchor-point and the marker bias was found. However, the VAS valuations were significantly affected by the context of the set of health states in the scaling task. CONCLUSION: Advanced methodologies should be incorporated in VAS valuation studies to deal with the context bias.
Authors: J Alonso; G Vilagut; S Chatterji; S Heeringa; M Schoenbaum; T Bedirhan Üstün; S Rojas-Farreras; M Angermeyer; E Bromet; R Bruffaerts; G de Girolamo; O Gureje; J M Haro; A N Karam; V Kovess; D Levinson; Z Liu; M E Medina-Mora; J Ormel; J Posada-Villa; H Uda; R C Kessler Journal: Psychol Med Date: 2010-06-16 Impact factor: 7.723
Authors: Anne M Gadermann; Jordi Alonso; Gemma Vilagut; Alan M Zaslavsky; Ronald C Kessler Journal: Depress Anxiety Date: 2012-05-14 Impact factor: 6.505
Authors: David H V Vogel; Mathis Jording; Carolin Esser; Amelie Conrad; Peter H Weiss; Kai Vogeley Journal: Sci Rep Date: 2022-09-01 Impact factor: 4.996
Authors: Daphne C Voormolen; Suzanne Polinder; Nicole von Steinbuechel; Yan Feng; Lindsay Wilson; Mark Oppe; Juanita A Haagsma Journal: Qual Life Res Date: 2020-07-15 Impact factor: 4.147