Afentoula Mavrodi
University of Macedonia, Greece
Scientific Tracks Abstracts: Prim Health Care
This study aimed at examining the test-retest reliability of an instrument developed to: a) elicit a monetary value
on a quality-adjusted life-year (QALY) using the Willingness-to-Pay (WTP) approach, within the Contingent
Valuation Method (CVM); and b) capture general populationâ??s motives regarding value assignment. Validation of this
instrument constitutes part of a PhD research for which the candidate holds a scholarship from Onassis Foundation.
WTP was elicited in two ways (iterative closed-ended bidding system/open-ended question). Participants’ motives
were assessed through 3 and 4 follow-up statements designed for those willing to pay for the hypothetical treatment
and those not willing to pay (protest bidders), respectively.
The study was conducted in Thessaloniki, Greece, during October/November 2018. A randomly selected sample
responded via telephone interviews on two occasions over a period of 4 weeks (n=97). Differences between the two
points in time were evaluated using the Wilcoxon signed ranked test. Test-retest reliability was assessed using the
intra-class correlation coefficient.
WTP estimates showed no statistically significant differences between the two points in time (p>0.05). Test-retest
reliability was acceptable and very good for WTP and WTP per QALY estimates, respectively (ICC values of 0.67
(95% CI: 0.51, 0.78) and 0.85 (0.73, 0.91), respectively). Analysis revealed high reliability for all three motivation
statements with coefficients ranging from 0.84 (0.67, 0.92) to 0.89 (0.89, 0.96). 3 out of 4 statements formulated
exclusively for protest bidders showed acceptable/very good reliability (ICC values ranging from 0.84 (0.67, 0.92) to
0.89 (0.78, 0.95)). After excluding outliers, ICC for WTP estimates was improved at 0.93 (0.88, 0.96).
Afentoula Mavrodi is a Ph.D. Candidate at the Department of Business Administration, University of Macedonia, Greece. She holds a M.Sc. in International Health Management with Distinction from Imperial College London. She has worked as a consulting analyst in London and as a freelance consultant in both public and private sector healthcare institutions in Greece. For her Ph.D. research she holds a scholarship from Onassis Foundation.
E-mail: amavrodi@uom.edu.gr
