Published in:
Open Access 01-07-2013 | Original Paper
The effects of lead time and visual aids in TTO valuation: a study of the EQ-VT framework
Published in: The European Journal of Health Economics | Special Issue 1/2013
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Background
The effect of lead time in time trade-off (TTO) valuation is not well understood. The purpose of this study was to investigate the effects on health-state valuation of the length of lead time and the way the lead-time TTO task is displayed visually.
Methods
Using two general population samples, we compared three lead-time TTO variants: 10 years of lead time in full health preceding 5 years of unhealthy time (standard); 5 years of lead time preceding 5 years of unhealthy time (experimental); and 10 years of lead time and 5 years of unhealthy time, presented with a visual aid to highlight the point where the lead time ends (experimental). Participants were randomized to receive one of the lead-time variants, as administered by a computer software program.
Results
Health-state values generated by TTO valuation tasks using a longer lead time were slightly lower than those generated by tasks using a shorter lead time. When lead time and unhealthy time were presented with visual aids highlighting the difference between the lead time and unhealthy time, respondents spent more time considering health states with a value close to 0.
Conclusions
Different lead-time time trade-off variants should be carefully studied in order to achieve the best measurement of health-state values using this new method.