Presentation (CTI)

OBJECTIVES: To evaluate and compare closed-ended bidding Willingness-to-Pay (CEB-WTP) and open-ended Scenario-Based (OE-SB) approaches for estimating the intangible costs of epilepsy in Saudi Arabia.
METHODS: A cross-sectional survey was conducted among 419 patients with epilepsy at a tertiary hospital in Saudi Arabia. Data were collected using a structured questionnaire including socioeconomic and clinical characteristics, an open-ended self-bidding willingness-to-pay method (OE-SB), and a closed-ended bidding method (CEB-WTP). In the OE-SB, participants stated their maximum monthly willingness-to-pay to eliminate epilepsy-related intangible burdens. In the CEB-WTP, participants were presented with an initial bid; accepted bids were doubled and rejected bids were halved until the maximum willingness-to-pay was identified. The two methods were compared using seven predefined criteria: competence, concordance, extreme outliers, and construct validity assessed via correlations with income, utility, clinical status, and disease severity. Non-concordance was defined as failure to accept in CEB-WTP the OE-SB value.
RESULTS: CEB-WTP generated higher mean estimates than OE-SB (2785.85 SAR vs 1566.35 SAR), with higher concordance (100% vs 97.58%) and fewer extreme outliers (0 vs 8). Competence was similar in both approaches (99.05% vs 99.76%). Correlations with income (r =0.033 vs r =0.106), utility (r = -0.117 vs r =-0.138) disease severity (r =0.135 vs r =0.124), and clinical status (r =0.083 vs r=0.064) were also comparable.
CONCLUSIONS: The CEB-WTP approach demonstrated superior performance in estimating the intangible burden of epilepsy, generating higher willingness-to-pay values, complete concordance, and no extreme outliers while preserving comparable validity across key socioeconomic and clinical measures. These findings support the use of CEB-WTP as a preferred method for quantifying epilepsy-related intangible costs in the Saudi population.