title: South Korean time trade-off values for EQ-5D health states: modeling with observed values for 101 health states.
abstract: OBJECTIVE
  This study establishes the South Korean population-based preference weights for EQ-5D based on values elicited from a representative national sample using the time trade-off (TTO) method.
  
  
  METHODS
  The data for this paper came from a South Korean EQ-5D valuation study where 1307 representative respondents were invited to participate and a total of 101 health states defined by the EQ-5D descriptive system were directly valued. Both aggregate and individual level modeling were conducted to generate values for all 243 health states defined by EQ-5D. Various regression techniques and model specifications were also examined in order to produce the best fit model. Final model selection was based on minimizing the difference between the observed and estimated value for each health state.
  
  
  RESULTS
  The N3 model yielded the best fit for the observed TTO value at the aggregate level. It had a mean absolute error of 0.029 and only 15 predictions out of 101 had errors exceeding 0.05 in absolute magnitude.
  
  
  CONCLUSIONS
  The study successfully establishes South Korean population-based preference weights for the EQ-5D. The value set derived here is based on a representative population sample, limiting the interpolation space and possessing better model performance. Thus, this EQ-5D value set should be given preference for use with the South Korean population.
authors: Division of Chronic Disease Surveillance, Korea Centers for Disease Control and Prevention, Seoul, Korea.
authors: Yeon-Kyeng
authors: YK
authors: Lee
authors: Hae-Sung
authors: HS
authors: Nam
authors: Ling-Hsiang
authors: LH
authors: Chuang
authors: Keon-Yeop
authors: KY
authors: Kim
authors: Hae-Kyung
authors: HK
authors: Yang
authors: In-Sun
authors: IS
authors: Kwon
authors: Paul
authors: P
authors: Kind
authors: Sun-Seog
authors: SS
authors: Kweon
authors: Young-Tack
authors: YT
authors: Kim
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D015233:Models, Statistical; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D019057:Quality-Adjusted Life Years; D012044:Regression Analysis; D056910:Republic of Korea; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D013223:Statistics as Topic; D013997:Time Factors; D055815:Young Adult