Abstract
BACKGROUND: The application of the time tradeoff (TTO) method in temporary health states may lead to less valid results because an unrealistic scenario is presented to patients. The chained TTO has been proposed to solve this problem. OBJECTIVES: To compare a chained TTO method with a conventional TTO method in the valuation of temporary health states, in terms of consistency and reliability. To compare both TTO methods with direct rating. PATIENTS AND METHODS: Eighty-four patients treated with oral anticoagulants were interviewed twice. During the 1st interview, values for 5 temporary health states were obtained with a rank ordering procedure, direct rating, and the chained TTO method. During the 2nd interview, either the 1st interview was repeated (n = 30) or health state values were obtained with the conventional TTO method (n = 54). Consistency was assessed by comparing the 3 valuation methods with the rank ordering procedure. Generalizability theory was used to assess reliability. RESULTS: The 3 methods produced significantly different valuations of health states. Chained TTO values were higher than values obtained with direct rating and the conventional TTO. Consistency and reliability did not differ across the 3 methods. CONCLUSION: The authors found no evidence for a difference in consistency and reliability between the chained TTO method and the conventional TTO method in the valuation of temporary health states. As direct rating is simpler to administer than both TTO methods, one could consider using direct ratings for the valuation of temporary health states. Biases associated with the conventional and the chained TTO method are discussed.
