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. 2015 Apr 9;10(4):e0122760. doi: 10.1371/journal.pone.0122760

Table 1. Methodology difference in WTP per QALY.

Study Characteristics Frequency (%) References
Total number or articles reviewed 14
Publication year
  1994–1999 1 (7.14) [29]
  2000–2005 3 (21.43) [21,22,28]
  2006–2010 4 (28.57) [6,19,23,34]
  2010–2014 6 (42.86) [20,2427,33]
Region
  Europe 7 (50.00) [19,20,2224,29,33]
  Asia 3 (21.43) [2527]
  America 3 (21.43) [21,28,34]
  Asia, Europe, America and Australia 1 (7.14) [6]
Sample respondent
  General population 9 (64.29) [6,1926]
  Patient 3 (21.43) [28,29,33]
  General population and Patient 2 (14.29) [6,34]
Sample size
  101–500 3 (21.43) [21,28,29]
  501–1,000 4 (28.57) [23,27,33,34]
  More than 1,000 7 (50.00) [6,19,20,22,2426]
Mode of administration
  Interview 10 (71.43) [19,20,2224,2629,33]
  Internet 2 (14.29) [6,25]
  Internet and telephone 1 (7.14) [34]
  Interview and telephone 1 (7.14) [21]
Number of Scenarios per study
  1 scenario 5 (35.71) [6,2729,33]
  2–10 scenarios 3 (21.43) [21,26,34]
  11–20 scenarios 2 (14.29) [23,25]
  More than 20 scenarios 4 (28.57) [19,20,22,24]
WTP Elicitation Method (WEM)
  Contingent Valuation
    Open-ended question 1 (7.14) [21]
    Bidding game 3 (21.43) [27,28,33]
    Card sorting procedure 2 (7.14) [23,24]
    Single-bounded dichotomous choice 1 (7.14) [29]
    Double-bounded dichotomous choice 2 (14.29) [6,25]
    Bidding game follow open-ended question 1 (7.14) [34]
    Payment scale follow open-ended question 1 (7.14) [20]
    Open-ended question or bidding game 1 (7.14) [26]
    Open-ended question and Payment card 1 (7.14) [19]
Discrete choice experiment
    Closed-ended question 1 (7.14) [22]
Number of WEM per study
  1 type 13 (92.86) [6,2029,33,34]
  2 types 1 (7.14) [19]
Utility Elicitation Method (UEM)
Not using UEM 1 (7.14) [6]
Direct Method
  Time-trade off (TTO) 1 (7.14) [34]
  Standard gamble (SG) 1 (7.14) [23]
  SG or TTO 1 (7.14) [24]
  TTO and VAS 1 (7.14) [26]
  Rating scale and TTO 1 (7.14) [29]
  TTO VAS and SG 2 (14.29) [21,28]
Indirect method
  EQ-5D 3 (21.43) [20,22,25]
  EQ-5D and SF-36 1 (7.13) [27]
Direct method and Indirect method
  Rescaling VAS and EQ-5D 1 (7.14) [19]
  VAS and EQ-5D 1 (7.14) [33]
Number of UEM per study
  No 1 (7.14) [6]
  1 type 5 (35.71) [20,22,23,25,34]
  2 types 6 (42.89) [19,24,26,27,29,33]
  3 types 2 (14.29) [21,28]