The results of this study do not support the common view that RS values are lower than TTO values , may suggest that TTO biases largely cancel , and support the validity of formulas for correcting SG bias
Background .
A common assertion is that rating scale ( RS ) values are lower than both st and ard gamble ( SG ) and time tradeoff ( TTO ) values .
However , differences among these methods may be due to method specific bias .
Although SG and TTOs suffer systematic bias , RS responses are known to depend on the range and frequency of other health states being evaluated .
Over many diverse studies this effect is predicted to diminish .
Thus , a systematic review and data synthesis of RS-TTO and RS-SG difference scores may better reveal persistent dissimilarities .
The purpose of this study was to establish through systematic review and meta- analysis the net effect of biases that endure over many studies of utilities .
Comparison of the Health Utilities Index Mark 3 (HUI3) and the EuroQol EQ-5D in patients treated for intermittent claudication
The Health Utilities Index Mark 3 ( HUI3 ) and the EuroQol EQ-5D ( EQ-5D ) were compared to each other and to other quality -of-life ( QoL ) measures in patients treated for intermittent claudication . A total of 88 patients with intermittent claudication completed the HUI3 , EQ-5D , R AND 36-Item Health Survey 1.0 , time tradeoff , st and ard gamble , and rating scale before revascularization and at follow-up at 1 month , 3 months , and 1 year . The effect of treatment on the HUI3 and EQ-5D dimensions and the overall scores , calculated using published formulas based on societal preferences , were compared . After 1 month of treatment , the majority of patients showed improvement on the HUI3 dimensions ambulation and pain and on the EQ-5D dimensions mobility , usual activities , and pain/discomfort . The mean HUI3 score was significantly higher than the mean EQ-5D score ( 0.66 and 0.57 , respectively , p < 0.01 ) before treatment . After treatment , however , they were not significantly different from each other ( e.g. , 12 months after treatment : 0.77 and 0.75 , respectively ( p > 0.05 ) . After 1 month , the scores did not change significantly over time ( p > 0.05 ) . The intraclass correlation coefficient between changes over time in the HUI3 and EQ-5D scores was 0.30 , with other health-related quality -of-life ( HRQoL ) measures the correlations for HUI3 and EQ-5D were very similar . In conclusion , both the HUI3 and EQ-5D demonstrated an effect of treatment in patients with intermittent claudication ; in addition , they showed similar relationships with other ( HRQoL ) measures . To demonstrate the effect of revascularization in patients with intermittent claudication , however , clinicians and research ers should be aware of the differences in the mean HUI3 and EQ-5D scores
The results of this study do not support the common view that RS values are lower than TTO values , may suggest that TTO biases largely cancel , and support the validity of formulas for correcting SG bias
Background .
A common assertion is that rating scale ( RS ) values are lower than both st and ard gamble ( SG ) and time tradeoff ( TTO ) values .
However , differences among these methods may be due to method specific bias .
Although SG and TTOs suffer systematic bias , RS responses are known to depend on the range and frequency of other health states being evaluated .
Over many diverse studies this effect is predicted to diminish .
Thus , a systematic review and data synthesis of RS-TTO and RS-SG difference scores may better reveal persistent dissimilarities .
The purpose of this study was to establish through systematic review and meta- analysis the net effect of biases that endure over many studies of utilities .