- Time-trade-off
Time-Trade-Off (TTO) is a tool used in
health economics to help determine the quality of life of a patient or group. The individual will be presented with a set of directions such as:Imagine that you are told that you have 10 years left to live. In connection with this you are also told that you can choose to live these 10 years in your current health state or that you can choose to give up some life years to live for a shorter period in full health. Indicate with a cross on the line the number of years in full health that you think is of equal value to 10 years in your current health state. [cite journal |author=Burstrom et al |title=A comparison of individual and social time-trade-off values for health states in the general population |journal=Health Policy |volume=76 |year=2006 |pages=359–370 |issue=3 |doi=10.1016/j.healthpol.2005.06.011]
The line is usually ranges from 1 to 10 and the person's score is calculate by dividing the number corresponding to their cross by 10. For example if someone marks a cross at 5 on the TTO line, they would be given a TTO score of .50. This number is often used in turn to calculate
Quality-adjusted life years or QALYs. In our example if this person were to live for 4 years at their current health state this would be equal to 2 QALYs (4 * .5). QALYs enable health care decision makers to combine mortality and morbidity into a single interval scale.Other tools that are used to determine health utility are the
Visual Analog Scale (VAS), theStandard Gamble Method, TheEQ-5D , theHealth Utilities Index (HUI)etc.References
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