Table 3

Patient preferences for the whole sample (n=174)
Whole sample
Regression1 Incremental WTP2(£) Their preference is for:
Value (SD) Value (SD)
ASCSURGERY Coefficient 1.4200 (0.253) 458.06 - Surgery (compared with current situation)
ASCCREAM Coefficient 2.8700 (0.398) 925.81 - Imiquimod cream (compared with current situation)
COST Coefficient −0.0031 (0.000) - - Decreased cost
CHANCE Mean 0.1090 (0.018) 35.16 (38.71) increased chance, 82% of respondents
SD 0.1200 (0.022)
MILD SIDE EFFECTS Mean 1.3800 (0.314) 445.16 (541.94) mild side effects (compared with severe, 79% of respondents)
SD 1.6800 (0.282)
MODERATE SIDE EFFECTS Mean 0.8390 (0.265) 270.65 (199.68) moderate side effects (compared with severe, 91% of respondents)
SD 0.6190 (0.396)
NORMAL APPEARANCE Mean 1.0200 (0.265) 329.03 (267.74) normal appearance (compared with severe change, 89% of respondents)
SD 0.8300 (0.333)
MODERATE CHANGE IN APPEARANCE Mean 0.5400 (0.345) 174.19 (548.39) moderate change (compared with severe change, 62% of respondents)
SD 1.7000 (0.274)
Number of respondents 174
Number of observations 2765 (=171 respondents *16 choices +1respondents*14 choices+1 respondent*8 choices+ 1 respondent*7 choices)
Log-likelihood −2013.9
Adjusted Rho-square 0.333
LR statistic 2047.47

1The preferred model is a MLM and presents all characteristics (apart from ‘COST’, ‘ASCSURGERY’, ‘ASCCREAM’) as random and independently normally distributed. The simulation process is based on 500 draws. All coefficients (either fixed or random) and the standard deviations of the random coefficients are statistically significant at 95%. 2WTP estimates are based on the regression results in column 3 and rounded to 2 decimal places. The standard deviations are in parentheses. Marginal WTP for a unit change in a treatment characteristic = (mean coefficient of characteristic)/-(coefficient ‘COST’), with SD = (SD of characteristic coefficient)/-(coefficient ‘COST’).

Note: Alternative specific constants (ASC) for surgery (ASC SURGERY) and for cream (ASC CREAM) show the preferences of these alternatives relative to the current situation, everything else being equal.

Key: SD = standard deviation, WTP = Willingness to Pay, LR = Likelihood Ratio.

Tinelli et al.

Tinelli et al. BMC Dermatology 2012 12:19   doi:10.1186/1471-5945-12-19

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